Aborted Arc: The prerevision comics were leading up to the Planeswalker War, but the comic line was cancelled before it could be published. Some of the characters involved, like Freyalise, Taysir and Tevesh Szat have turned up later in modern storylines, but details on what actually went down are extraordinarily vague.
Absurdly Spacious Sewer: Those in the city-world of Ravnica (they're Ravnica's swamps/black mana sources). They're so vast, they're called the "Undercity".
After the End: Several times. There's the downfall of the Thran, the sylex blast that started the Ice Age, the Apocalypse set, the coming of Karona, and finally, Time Spiral block, which is the closest to the trope. (Of course, it's Time Spiral, so it's before, after, and three seconds to the left of the end.)
A.I. Is a Crapshoot: Memnarch, a golem left behind by the creator of Mirrodin to guard the plane, goes insane and tries to become a planeswalker itself.
Alien Invasion: Phyrexia is another plane rather than another planet, but Alien Invaders is a spot-on description of its role in the Invasion and Scars of Mirrodin blocks. They even have giant spaceships with laser beams and everything (seen fighting Urza's Powered Armor on Searing Rays, for example).
Mirrodin has four (later five) moons — which shine, and thus are also interchangeably called suns. There's no indication that it has any normal suns, either...
Also, Dominaria has two moons (although one of them got blown up), and Esper's night sky is covered in a grid, making it appear like a huge star chart.
Esper gets even screwier when it rejoins the other 4 shards. Many cards from Alara Reborn feature skies with visible boundaries from what was once one plane and what was another.
Alternate Universe: Planar Chaos, which shows a hundred alternate Dominarias, such as one where bad guy Braids, Cabal Minion becomes helpful Braids, Conjurer Adept. Some of these cards were genuine "What If?" questions, others were "This card is functionally identical to a classic of a different color, and given the colors' general traits should/could have been printed in this color from the start." (And in the case of the aforelinked Pyromancer, would eventually be printed in the new color.)
Alternative Calendar: Dominaria has one—denoted as AR, for "Agrivian Reckoning," with year 1 being the birth of Urza and Mishra.
Anachronism Stew: Various minor examples. Any given expansion encompasses some length of time, so sometimes you have cards in the same set representing notably distant points in the time line.
Ancient Grome: Almost averted in Theros, where the set's designers consciously decided to focus on Greek rather than Roman influences. A few Roman influences have slipped through however, e.g. Raised by Wolves.
And Man Grew Proud: In the Zendikar expansion, the Eldrazi once terrorized the plane, but were sealed away long ago. Now, they're remembered only in scraps of legends, and their true nature has been forgotten. Many believe them to be ancient gods who created the plane. Of course, in Rise of the Eldrazi, they get unsealed...
Anti-Villain: Apparently, the Red Phyrexians of New Phyrexia. They are hardly good or kind people, but the influence of red mana remains strong, rendering them capable of independent thought, creativity, and even mercy and compassion. They even seem opposed to what they see as cruelty, which would include a lot of the actions other New Phyrexian factions have taken.
Appropriated Appellation: Tezzeret was never given a name by his father. Growing up in the slums, his peers gave him the nickname "Tezzeret", meaning 'a concealed, improvised weapon' after he won a fight with a bully by shivving him. The name stuck.
Spirit patrons raging over the kidnapping of one of their own? Kamigawa. A reconverting of five mini-planes into one singular plane? Shards of Alara. An unraveling of the strands of time? Time Spiral. How about the world changing every fifty or so years to a "dark" version? Lorwyn turns into Shadowmoor.Eldritch Abominations emerge from their prisons into a living world that hates their alien magic? Zendikar. A relentless evil that is essentially The Corruption personified and has been growing and festering in the core of the Plane ever since its creation finally amasses enough military power to launch a full-scale invasion headed by the twisted, corrupted husks of the Plane's own legendary heroes from ages past up to and including the Plane's creator himself? Scars of Mirrodin. Humans being exterminated en masse by zombies, werewolves, vampires, demons, possessed trees, and other unspeakable horrors of the night? Innistrad. Ten Guilds being forced to run a a maze in an attempt to either bring peace or destroy them all? Return To Ravnica.
Old-style planeswalkers who create their own artificial planes will eventually see their planes collapse and be utterly erased. It ultimately happened to Serra's realm, as well as Rath. No word on Argentum/Mirrodin yet...
Mirrodin hasn't collapsed, per se, but it has been compleated and transmogrified into New Phyrexia. Nothing remains of Mirrodin but the moons.
Ascended Meme: The legend of a player who shredded their (now-expensive, but then worth maybe a dollar) Chaos Orb card to win a game (it destroys any card it touches when dropped onto the field) eventually got acknowledged in the Unglued set as Chaos Confetti, which instructs the player to shred the card for the same effect.
Toshiro Umezawa, of Kamigawa block; a rare black-aligned protagonist. (This block also featured a white-aligned antagonist; this is perhaps made more understandable still when you consider Kamigawa is based loosely on the Japanese Shinto religion, and East Asian cultures tend to view white as the color of death.)
Also these channelers, who like the aforementioned Shadowmoor cycle, have two separate class types listed to reflect both participants.
Ajani Goldmane's unique brand of magic is the ability to bring out and manifest the best and strongest aspects of another person in physical form. His preferred brother in arms? His elder brother, Jazal Goldmane. Together they were said to be unstoppable.
Batman Gambit: In his mission to destroy Phyrexia, Urza deliberately included Tevesh Szat, a Token Evil Teammate, in his group because he correctly predicted that said teammate would betray them. Urza had invented a way to turn a soul into a Fantastic Nuke, but in order to use it, he would need to destroy the soul of a fellow planeswalker, and Tevesh Szat's inevitable betrayal would give Urza an excuse to kill him and power the bomb.
Big Bad: There are two big contenders and several others:
The mechanical demon-god Yawgmoth in pretty much all of the storylines from Antiquities to the end of the Weatherlight saga was arguably the most powerful being in The Multiverse. And even long after his death, his creation, Phyrexia, lives on, and is now infecting Mirrodin.
Much later, during the Alara storyline, the elder dragon Nicol Bolas (a character from the game's early days) stepped in as the foremost threat to Dominia's stability.
There have been a few other, smaller Big Bads in between, including the vampire overlord Baron Sengir in Homelands, the golem wizard Memnarch in Mirrodin (himself a victim of the Phyrexian taint), and the corrupt human king Daimyo Konda in Kamigawa.
The primary goal and identity of the Simic guild of Ravnica is artificially engineering superior life-forms. Their guild mechanic is "Graft", which is flavored as attaching cytoplast modifications to creatures.
And in the Gatecrash set, Simic's new shtick is the "evolve" mechanic, in which their creatures augment themselves, ostensibly by mimicking the favorable traits of other creatures they spend enough time around.
In an odd example, Phyrexia biologically augments non-biological creatures.
Bittersweet Ending: The ending to the Godsend novel is a pretty cruel one. Xenagos is slain and order returned to Theros, but Elspeth is killed, Heliod gets away with everything, and Elspeth's sacrifice turns out to be senseless as it condemns a Returned Daxos to a shadow of life searching endlessly for her.
Ghostfire. Colorless damage basically got the reaction "hmm, interesting..." but it didn't become important until the Zendikar block, where it turned out Ghostfire was part of the key to the lock holding in the Eldrazi.
Subverted by the same block's Steamflogger Boss, which it was openly admitted was created solely as a joke—there are no riggers besides this (and those changelings that count as every creature type), "assemble" has no in-game meaning, and there are no Contraptions note although Contraption is a recognized Artifact subtype in the comp. rules, and there supposedly never will be. (Admittedly, this is a bit hard to take seriously when one takes into account The Unreveal below and "Whenever a goblin with goblin goblins, etc.")
Les Collaborateurs: Nicol Bolas's many minions in the Alara block surreptitiously working to spread paranoia and anarchy throughout their worlds — the xenophobic Knights of the Skyward Eye from Bant, expansionist Seekers of Carmot from Esper, corrupt merchant Gwafa Hazid, and barbarian shaman Rakka Mar. As of Mirrodin Besieged, he's got Tezzeret helping him out in Mirrodin.
Corpse Land: The plane of Grixis is inhabited by dead things, undead things, demons, and the occasional desperate necromancer. Due to a lack of green or white mana it's incapable of producing new life.
Dark Is Not Evil: While Black often tends to produce villains, it has at least a few protagonists under it who don't fit on the worse levels of anti-hero, like Toshiro Umezawa and Xantcha. Some other protagonists are also half Black, half any other colour, like Teysa Karlov (Black/White).
Dark World: Lorwyn is based on the idyllic, fairy tails of the British Isles. Shadowmoor is its dark reflection and takes more after the Brothers Grimm...
Dating Catwoman: Ashnod and Tawnos are in love, despite being generals on the opposing sides of the Brothers' War.
Die or Fly: Severe physical or emotional trauma is the catalyst to a Planeswalker igniting their latent spark.
Old school, demi-God Planeswalker examples:
Nicol Bolas ascended as he fought the other four Elder Dragons, allowing him to win their war and become the last surviving one.
Sorin Markov's grandfather Edgar turned him into a vampire (the second one to ever exist in Innistrad with Edgar being the first) with a Blood Magic fuelled demonic pact. The ritual was so traumatizing that it ignited Sorin's spark.
Urza Planeswalker, at the climax of the Brothers War, sets off the Golgothian Sylex, which sends all of Dominaria into a centuries-long ice age. His latent spark activated, allowing him to survive the blast.
Teferi, Mage of Zhalfir, while studying mind magic at the Tolarian Academy, fell into a bubble of slow time that was filled with fire and got trapped there. The intense damage activated his spark half-way, so that he was able to survive until another student could get him out with water from a different slow-time bubble. She became his favorite companion (in the Doctor Who sense) when they found out that, because of the two different slow-time bubbles, she aged at a dramatically slower rate than a normal human, causing her to fall under the rules of Really 700 Years Old.
Chandra Nalaar: Set fire to her village in a fit of rage after learning of her Arranged Marriage, and ran and hid. A local Knight Templar organization noticed, and not believing the villager's claims that the destruction was caused by a single child, rounded up the villagers and sealed them into the burning huts, punishment for harboring pyromancers. Chandra returns just in time to hear her family dying, and is quickly subdued by the soldiers. Just as they are about to behead her, her Spark ignites at the last possible second.
Sarkhan Vol was born onto a plane that had been a haven for dragons, which had been hunted to extinction by the local warlords, much to the dismay of the local shamans that worshiped them as the ultimate predators. Drifting back and forth between tribes and armies, searching for a purpose, making a name for himself in the process as a powerful warrior, Sarkhan enters into a trance after slaying an opposing commander, where he encounters the spirit of a dragon. So, inspired by the beast's majesty, he ascends killing his and the opposite army in the process.
Tezzeret, after being repeatedly denied entry into the Seekers of Carmot, breaks into their vault to prove his worth by crafting his own Etherium. He discovers the vault to be empty and that the Seekers' claims of the ability to craft new Etherium was a lie. Their plane is depleted, and they are merely recycling old Etherium. Caught in the act by the guards, they catch him and beat him half to death. The thought of his entire life's work being for naught was so harrowing that he ascended on the spot.
Ajani Goldmane's spark ignited when he discovered his brother Jazal had been murdered.
Dropped a Bridge on Him: Poor Ertai. First he was our resident smug snarker, and then the plot for Nemesis turned him into a more heroic character and even put him into a tragic love story... and then immediately turned him into a horrible bad guy and later killed him off in the most embarrassing way possible. Granted, his original personality did lend itself to a Face-Heel Turn, but the way it came about and the extremes it went to were just weird.
The plane of Mirrodin has five suns. There is night time, but it's brief and exaggerated. Basically the only reason this is worth mentioning is the flavor text on Grasp of Darkness.
The plane of Serra is bathed in the light of a perpetual sunrise.
In Lorwyn "the sun never quite dips below the horizon".
The End of the World as We Know It: A particularly common trope. At one point, after several sets revolving around ever-bigger wars and cataclysms, the designers moved the action to Lorwyn, a new, rural-themed setting that scaled down the conflict: tribes battling neighboring tribes over land and prestige. Months later, yup, the whole world was wrecked. As in, the sun stopped shining (and few remember that it ever did!). So much for that.
Enemy Civil War: There are some major tensions growing between and even within the five Phyrexian factions that conquered Mirrodin, and the liberation of Karn might just be the spark needed to ignite a full-out war among the New Phyrexians.
Engagement Challenge: In The Brothers' War, the Warlord of Kroog, searching for a powerful warrior to wed his daughter, decrees that whoever can move a giant jade statue from one end of the palace courtyard to the other will win the hand of Princess Kayla. Urza completes the challenge by building an automaton to lift the statue.
Eunuchs Are Evil: The expansion Portal: Three Kingdoms has a card called Corrupt Eunuchs.
Kamigawa is a battle fought between humans and kami, who, due to the nature of Shinto, live in everything.
And taken Up to Eleven in Zendikar, where the "Roil" dramatically changes the landscape every few months, weird gravity wells cause floating islands of grassy plain that can drop at any moment, and the creatures that are not killed by the landscape are as hard as your average video game mid-boss. Rise of the Eldrazi then kicked that eleven up to twelve, because the usually unpleasant wildlife is being supplanted by Eldritch Abominations.
In Scars of Mirrodin, the entire plane is being taken over by the Phyrexian Glistening Oil. Metal becomes flesh, flesh becomes metal, and havoc and chaos ensue.
In Innistrad, humanity is the bottom of the food chain. Werewolves and vampires see humans as tasty snacks, ghoulcallers and stichers raise the dead for kicks, giests torment humans out of rage (or because they don't know any better), monsters lurk in the woods to snatch up the unwary, and demons lurk in the shadows, corrupting humanity to gain a foothold into their world.
Evil Chancellor: In Time Streams, Radiant's war minister turns out to be a Phyrexian spy, secretly working to subvert and corrupt Serra's Realm.
All over the place; look at White Knight versus Black Knight, for example. The entire Shadowmoor set, as a dark mirror of the earlier Lorwyn set, features many opposite counterparts to specific cards from the Lorwyn block.
One of the terminologies of the game is "Mirrored Pair". These tend to be two cards who are polar opposites of eachother. Generally they tend to be this trope (although certain examples, like Hero of the Bladehold and Hero of Oxidda Ridge who are both "good", are exceptions).
Since the story details a different plane almost every block, the addition of new planes could be considered this to Dominia. Then again, in a theoretically infinite multiverse, it's justified.
Dominaria was also subject to this. While nowadays, the story just focuses on a new plane when a new theme for the setting is needed, as early as Fallen Empires and as recent as Odyssey while new continents would just be added to Dominaria to fit this purpose. This leads to Dominaria being so diverse - while most other planes are only themed around a single culture or gimmick, Dominaria has typical Medieval European Fantasy fare in Terisiare, Aerona, and Corondor; Reniassance-era technology in Caliman; wartorn Vestigial Empires in Sarpadia; Conan-esque Heroic Fantasy in Otaria; a Western Africa analogue in Jamuraa; and a Wutai in Madara, among others. And that isn't taking into consideration the areas from Rath that were fused with Dominaria in the Overlay.
The Golgothian Sylex was, functionally, a nuclear weapon. Its detonation ended the Brothers' War, vaporized Argoth, caused the Ice Age, and tore a literal hole in reality.
Yawgmoth repeatedly dropped "stonecharger" bombs on his enemies in The Thran which not only resembled nuclear weapons in their destruction, but also caused the same sort of horror real nukes inspire in at least one of the characters.
Nearly all of Magic's angels are visibly female. The overwhelming majority of Magic's demons are so freakish looking that the idea of having a gender seems a moot point. Though the gender of either is largely a moot point, as, being magically created avatars of their respective colors, neither reproduce in the traditional manner.
Razia and Serra play this trope straight, although with reason; Serra was a human female Planeswalker who created her own plane, and all Boros Angels were basically clones of Razia herself, who was female.
Forgotten Friend, New Foe: Volrath, villain of the Tempest block, was once Gerrard's adoptive brother before they bitterly parted ways in their youth.
A Form You Are Comfortable With: Old-generation planeswalker are also shapeshifters, capable of changing their appearances at will. Most of them generally opt to stay in the form they look like just before their ascension though.
Gambit Pileup: Occurs during the original Ravnica trilogy when it turns out that all of the guilds are trying to conquer the plane.
Gambit Roulette: Nicol Bolas' ploy to free the Eldrazi certainly counts. To release the Eldrazi, he required the presence of three different planeswalkers at the Eye of Ugin, as well as having one of them use Ghostfire to trigger the failsafe mechanism. He could only be certain that his own minion (Vol) would be there, but to lure the other two, he combined elements of his own meticulous planning, as well as a simple stroke of luck. He even said so himself!
Bolas: I didn't send you to ensure no one entered the Eye. I sent you to ensure they did. Do you think it a coincidence that two planeswalkers arrived there when they did?
Vol: You sent me to fester? As a helpless proxy? You knew they would come?
After Arabian Nights, Antiquities attempted to tell an original story.
The "pseudo-block" of Legends, The Dark, and Fallen Empires. Legends was awesome, but neither The Dark nor Fallen Empires continued its mechanics, or its storyline, and were instead sequels to Antiquities.
Gods Need Prayer Badly: The Gods of Theros have strength directly tied to the number of worshipers the god has. In an example of Gameplay and Story Integration, the Gods cease to be creaturesnote but continue to be indestructible legendary enchantments when their controller does not have enough devotion to that god's color(-s)note Measured by the amount of colored mana symbols among permanents that player controls.
Hammerspace: Sash and Waistcoat, the two un-men and Those Two Guys from the Onslaught storyline, were designed by Ixidor to be living embodiments of Hammerspace. They're essentially living portals. There's several gags where they store things like pianos inside themselves.
Phyrexians, extra-dimensional, bio-mechanical nasties whose machine parts are grafted onto them upon birth.
Esper, one of the Shards of Alara, has this, as well. It's less grotesque than the Phyrexians, and is basically a way to transcend nature.
Holy Hand Grenade: White has plenty of this. Loads of priests, religions, angels, miracles and so on that all focus on cutting a swath of destruction. Half the time, even the "nice" life-gain and protection spells are there to enable that planeswalker to do something terrible to you with the next card.
Humanoid Abomination: Szadek, founder of the Dimir Guild is a ten-thousand plus year old and the last surviving member of his species, who are essentially psychic vampires. The name of his species? The Eldritch. Make of that what you will.
From the behind-the-scenes point of view, the prevalence and variety of humans does a couple of good things for the game. First, it lets us put a human face on every color of Magic. That helps the look and feel of all the colors stay appealing to a wide variety of players. Our market research shows that we have a lot of human beings among our consumers, and having human beings in the art gives those players a familiar face that they can identify with. [...]
Second, humans play an important role as a point of comparison in every color. You get to see how tall or tough or magic-inclined goblins are compared to humans, for example, since you get to see them next to red-aligned humans that live in similar environments and have similar color values. You get to see what role griffins or pterons or leonin play in a given setting, because you get to see white-aligned humans riding them or hunting them or making alliances with them. We can afford to get more exotic with our nonhuman races, in part because there are plenty of examples of humans next to whom you can see similarities and differences—and we like that.
Jidai Geki/Medieval Japan: A combination of these, plus elements of traditional Japanese fantasy and Shinto are the basis of the Kamigawa block.
Kangaroo Court: The card Twisted Justice is styled after creating such a situation, and the flavor text is from the perspective of the judge as he's being manipulated to send an innocent man to his death.
Kill 'em All: The Weatherlight saga had an extraordinarily high body count, especially among named protagonists.
Laser-Guided Amnesia: The in-game flavor of your deck is that of your memories, and a number of cards have the ability to search opponent's decks for cards and remove them from the game.
Legions Of Phyrexia: The Invasion block storyline has Dominaria defending itself against the invading forces of Yawgmoth.
Light Is Not Good: While White has several protagonists, it has occasionally proved to be oppressive, tyrannical and horribly misguided:
Takeshi Konda is the primary example of a White Big Bad.
Also from Kamigawa is the Myojin of Cleansing Fire, another White villain. Although he doesn't get much "screen time", he is clearly fighting on the side of the kami, and is implied he destroyed his own mortal followers with his sacred flames.
Another evil White kami is Kataki, who, according to this side story, is pretty much insane.
As Phyrexia shows (more specifically, Elesh Norn and her servants), White can be quite scary too...
Pretty much the entire point of the White cards in The Dark.
According to Mark Rosewater and Serra (as well as some of his guises and spells), Urza is White/Blue. He also caused countless cataclysms, devised an eugenics program (and was a general social darwinist), manipulated his own allies against themselves and ultimately joined Phyrexia.
In the Theros Block, Heliod is the Bigger Bad, having provoked the conflicts in the pantheon and ultimately murdering Elspeth in cold blood.
Living Shadow: This is generally the flavor of the 'Shade' creature type.
Loose Canon: The game's original dozen spin-off novels were published by HarperPrism. When the Weatherlight saga began and Wizards of the Coast started its own novel line, the continuity was revised (This is commonly referred to as "The Revision"). Any material in the old novels is considered Canon unless new material directly contradicts it.
Love It or Hate It: Invoked with Schismotivate, which works by inciting strong positive and negative emotions in two target creatures. The happy creature gets powered up; the sad creature gets powered down.
Love Redeems: Belbe, in Nemesis, leading to Redemption Equals Death. Spoiled somewhat by the romance being with Ertai, who went over to the side Belbe abandoned...before her body had actually cooled.
Yawgmoth behind Volrath, and in general Phyrexia for Rath.
Phyrexia would be this to Memnarch as well, but it's a complicated case: Memnarch was curtailing the mycosynth, the first signs of Phyrexian infection. When he was removed, the mycosynth could grow unchecked.
Mary Sue: A rare in-universe example; Akroma was created by Ixidor, a mage that could turn his fantasies into reality, as an idealized homage to his dead lover, and existed primarily to lay waste to his enemies. Her card reflects the concept, with its over-the-top amount of abilities.
Glissa Sunseeker discovered (as far as the surface races are concerned) not only Mirrodin's fifth sun, which she also named, but also the mana core at the heart of the plane, meaning she's essentially found two suns.
Gideon Jura. Gideon translates to 'Powerful Warrior' and he is consistently portrayed as this, being one of the only planeswalkers who isn't a straight mage; he's more of a paladin instead. One of his card abilities also turns him into a 6/6 human soldier temporarily, making him quite powerful indeed.
Garruk Wildspeaker's specialty is that once he defeats a wild animal, he can commune with it and summon it to his aid at a moment's notice.
Ajani Goldmane was born with a rare genetic defect that gave him startlingly pale fur.
Rafiq means "friend" in Arabic. He is the most decorated paladin on his plane, and renders his services as a peacekeeper and mediator of sorts, trying to solve would be duels with both participating parties leaving satisfied.
Very literally on the plane of Lorwyn. The local giants live large in every conceivable way, including how they sleep, sometimes decades at a time. During this sleep, which they call the 'namesleep' they have any number of dreams where they imagine themselves in some sort of epic poem all most. They take this as a sign, and when they wake up they take on that persona and name themselves appropriately. Such as a wandering drifter named Rosheen Meanderer, or a peacekeeping arbiter named Galanda Feudkiller.
"Pyrexia" is a medical term for a fever. The Phyrexians, in addition to not being a very pleasant lot, use genetically engineered plagues. In fact, Yawgmoth started out making such plagues. Their name is also derived from the Greek letter Phi, which is commonly used to represent the "perfect" golden ratio (and is itself commonly used as their sigil), reflecting their collective superiority complex.
Morphic Resonance: The werewolves of Innistrad all have distinctive visual cues to make it clear that the wolf and the human are the same creature. When this isn't done through a repetition of the settingnote a la Tormented Pariah, it's done with Morphic Resonance, copying a physical detail on both sides. For example, Reckless Waif's distinctive pink hair, or Mondronen Shaman◊'s single glowing eye.
A Nazi by Any Other Name: Lorwyn's Elves believe that anything that is ugly is an affront to nature. Naturally, they believe this gives them the right to systematically hunt down and murder ugly lesser races.
In the novel for the Nemesis set, the Phyrexian Belbe was deliberately sabotaging the plans for Rath to overlay Dominaria. Until Eladamri killed her because she was constructed from his daughter's body.
In the Ravnica series, the Dissension novel has the Azorius Guildmaster explaining that things have gotten a lot worse because the main characters arrested the first book's Big Bad, who was put on trial and killed. How is this a bad thing? The magically-enforced government of Ravnica demands that group/entity exist, for the sole purpose of doing Big Bad things. Because it could no longer act as an opposing force, the magic of the Guildpact was weakened and could no longer protect the city.
Another one happened in In The Teeth of Akoum, Zendikar's novel. Upon reaching the eponymous location, Sorin Markov, a vampire planeswalker, tries to activate a strange device. Nissa, his unwilling partner, is a Zendikar native elf who hates vampires. When Nissa notices the device reacting to Sorin's ritual, she promptly uses a spell to destroy it. Unfortunately for her, and Zendikar, that device is the final lock which holds the Eldrazi, and with no more lock to hold them, they break free. Sorin, annoyed, leaves afterwards.
Earlier, in another example, Jace's, Chandra's and Sarkhan's shenanigans some time prior weakens the rest of the locks keeping the Eldrazi imprisoned, just as Nicol Bolas wanted.
Memnarch might not have been a nice guy, but he was fighting back the mycosynth corruption in Mirrodin's Core and preventing Phyrexia from taking hold there. When Glissa and her friends defeated him, the mycosynth grew unchecked and Phyrexia could grow unimpeded, dooming the plane.
Older than They Look/Really 700 Years Old/Time Abyss: Old generation planeswalkers are generally immortal; Urza, as an example, lived for at least 5000 years, while Nicol Bolas is even older. That's before counting some people who live long despite being otherwise mortal: Jodah aged slowly because he fell into a fountain of youth in his youth; Jhoira, unlike her planeswalker boyfriend Teferi, used slow-aging potions; Liliana Vess made a contract with demons (in her case, despite being a planeswalker, she is not normally immortal due to the Mending) and so on.
One Steve Limit: Enforced for gameplay reasons — all planeswalkers which appear or may appear on cards are required to have different names.
Our Dwarves Are All the Same: Dwarves are basically all blacksmiths and miners with large beards. If they're warriors, they wield axes. Even in Shadowmoor, whose Duergar dwarves have a radically different appearance, they're still primarily miners.
Our Elves Are Better: There are many different elf tribes in the setting, but the recent Lorwyn elves are a sharp departure from the previously base-green elves into green/black to show their arrogant destructiveness. (Shadowmoor flipped it so they became the plane's only protagonists, with even white turning paranoid, insular, and Hive Mind-ish.)
In Magic's debut set, elves were portrayed as feral and vicious, in startling contrast to the conventional concept (although those showed up in most other sets).
Also, the Elves of Deep Shadow of the classic set The Dark, later reprinted as part of the Golgari guild in Ravnica: City of Guilds, were green but produced black mana instead of green when tapped, and dealt damage to their controller each time they did.
Mirrodin's elves are basically cyborg elves. Mind you, everything on Mirrodin has a high metal content one way or another.
Organic Technology: Phyrexia. They invoke this trope, subvert it, divert it, avert it, deconstruct it, reconstruct it, and ask it out for dinner. Their entire purpose is to blur the line between 'organic' and 'technology' to the point of irrelevance. In the most nightmarish ways possible.
The Lorwyn block is a smorgasboard of this trope, featuring philosopher giants, Nazi elves, badass halflings, and monstrous-looking faeries.
The Shadowmoor block, a Bizarro Lorwyn, carries on with this trope, as the kithkin/halflings become paranoid castle-dwellers and merfolk become murderous fish-faced monsters.
Most of the races in Shadowmoor became personifications of their worst qualities: the giants become so lazy and mindless that they are mistaken for landmass, the goblins have degenerated from being impish tricksters to being wild animals, the treefolk have become utterly apathetic to the other races, and the cinders lost all of their passion and fire, and now want to make all the other races suffer like they do. The two exceptions are the elves, who have been humbled into nobility by being hunted and persecuted, and the faeries, who are protected by Oona's magic.
Each setting that has vampires that are quite recognizable as vampires, as with other typical fantasy species, they tend to make subtle little differences between one plane's vampires from another plane's:
Ravnica has psychic vampires like Szadek, some of which look extremely feral.
Zendikar's vampires have a very strong 'venomous' motif and had fang-like protrusions from most of their joints.
Rath's vampires are basically giant bats, and the villainous Evincar has a pack of vampire dogs as pets.
Mirrodin's vampires have their fangs in their fingers, which are basically foot long syringes, and their bowels are visible from the outside.
A major plot point in the Zendikar block novel In the Teeth of Akoum. The elf protagonist, Nissa Revane, doesn't realize one of her traveling companions, Sorin Markov, is a vampire until very late in the novel. This is due to the fact that since he's from Innistrad and not Zendikar, he has none of the staple characteristics of her world's vampires. This is unintentionally hilarious, as when the character was first teased by Wizards of the Coast, quite literally, the first thing the fan base learned about him was that he was a vampire.
Our Zombies Are Different: Pretty much all of the major variations of zombie show up on one plane or another. Innistrad even combines two different kinds, as it has mad science monsters in blue coexisting with Romero-style hordes of the flesh eating dead in black.
"Their forces are unknown to us. The Moriok or the nim that emerge from the necrogen bogs—those we understand. These horrors which pour out of the canyons use weapons, tactics and magic that are alien to even our most capable generals and seasoned warriors. Our armies are scattered. We have no choice but to hide and survive."
Parental Bonus: For a very brief time, Goblin Piker was going to be reprinted with the following flavor text: "Pike her? I barely even know her!"
Passion Is Evil: In it's early days, it pitied the wise, intellectual Blue colour with the passionate and excessively agressive Red. Nowadays, while Red still suffers from depictions as a bully, it is definitely by far depicted more heroically thanks to positive emotions like empathy, while Blue's sociopathic and deceptive side is played up.
Karn in Planar Chaos. While sealing the time rift over Tolaria, he senses a corruption in himself taking hold and flees to an undisclosed location. He doesn't reappear in the storyline for another four years.
Likewise, Nicol Bolas in Future Sight. He was, apparently, too awesome to kill off like everyone else, so instead he just left, giving him the opportunity to come back again later. (Which, in Alara block, he did.)
The sylex blast at the end of the Brothers' War prevented Gix from gaining a foothold in Dominaria and sealed Dominaria away from the rest of the multiverse, but it also leveled most of the Terisian continent and completely vaporized Argoth.
The battle for Serra's Realm. Urza's forces defeat the Phyrexians, but the fighting causes the entire plane to collapse.
Basically the whole campaign in the Invasion saga. The coalition wins, but Dominaria becomes a postapocalyptic wasteland.
The Thran managed to defeat the Phyrexians, but afterwards, their civilization was too weak to survive, and collapsed.
In the Time Spiral block, every time Teferi's team manages to close a time rift, they stabilize that area at the cost of a planeswalker's power and/or life.
Retcon: In addition to the game changes mentioned above, there have been changes to the game's story and background:
Summoned creatures were originally presented as being actual creatures from another universe, pulled across and enslaved by the caster; now, they're essentially magical copies.
The story of Coldsnap, essentially an entire set retconned onto the end of Ice Age block.
Then there's the "Revision". In the early days of Magic, the novels and comics where done by outside companies. Eventually (around the time of the Weatherlight Saga), Wizards of the Coast decided to publish their own books. They took this point to clear up and change some aspects of the canon, and said that, henceforth, the pre-revision books would be canon unless a post-revision book contradicted them.
Since it was a continuity and nostalgia heavy block, the Scars of Mirrodin saga retconned several parts of the original Mirrodin books and a few parts of the Weatherlight Saga, causing many headaches to fans.
Rent-a-Zilla: During the Dissension tie-in novel, Ravnica is attacked by giant monsters. First there's some Nephilim that grow giant-sized and start smashing things, then the Izzet's dragon guildmaster Niv-Mizzet flies in to fight them off, and eventually Experiment Kraj and Rakdos the Defiler join the fray as a result of a Gambit Pileup. Widespread destruction ensues.
Royally Screwed Up: Lord Konda, the mad king of Kamigawa. To gain immortality, he abducts an entity from the Spirit World, instigating a devastating war between mortals and spirits.
Rule of Symbolism: Urza ascends into (or even dies and is resurrected into, depending on your point of view) becoming a divinely powerful planeswalker after using the Golgothian Sylex. Golgotha, also known as Calvary, was in The Bible the place where Jesus Christ was crucified. To add to this, he bleeds into the chalice (which somewhat bears a resemblance to the Holy Grail) from a forehead wound. He'll then go on to be the primary opponent of a God of Evil who lives in Dante's Inferno-esque Hell-like realm.
Sand Worm: Wurms, which are essentially giant serpentine dragons, come in all shapes and sizes - including some that tunnel through solid ice.
Magic frequently visits settings that could easily described as hell on Earth, but they always make a point to have the cards showing off the landscape look incredible, even if that landscape is oh say, MADE OF DEAD PEOPLE.
Definitely the case in New Phyrexia. Some of the land art was based on what happened to the art in Scars block after Phyrexia got involved.
Sealed Cast in a Multipack: The Innistrad storyline features this. The Helvault, a giant silver mass, imprisons the legendary angel Avacyn, along with the demon she was fighting at the time, Griselbrand, and a whole host of other angels and demons. Needless to say, the Helvault eventually gets broken, in the expansion called Avacyn Restored.
Sealed Good in a Can: The angel Avacyn was dragged into the Helvault she made to seal away unkillable demons. Based on the mechanics of the Helvault card getting her out means freeing everything else inside.
Snakeform shows a snake slithering out of a pile of clothes that was once a mage.
Turn to Frog uses the same basic concept in its art, where "Target creature loses all abilities and becomes a 1/1 blue Frog until end of turn.".
As does Ovinize, which depicts a sheep among weapons and armor, whose name is similar to the Latin, Ovis aries.
Shock and Awe: Much less so than one would expect, most red elemental magic tends to use fire. Though there are plenty of shocking cards, such as the original damage spell.
Shoot the Dog: Pretty much Urza's whole hat. He does awful things in the name of protecting Dominaria from Phyrexia and Yawgmoth. At the end of the story, Dominaria ends up in shambles, but ultimately in better shape than Phyrexia. A pity that, however slowly, Phyrexia can regrow from a single drop of Glistening Oil.
Shoot the Shaggy Dog: During the Mirran-Phyrexian war, Venser, Koth, and Elspeth try to free Karn from Phyrexian influence. They even manage to free him from the taint via Venser's Heroic Sacrifice. And then Karn leaves Mirrodin and the Phyrexians win anyway.
Sinister Minister: Almost any black creature of the Cleric subtype falls under this trope.
It's more than possible to have multiple versions of the same specific thing from various points in the storyline in play at once; for example, there's nothing stopping you having both the Tolarian Academy and its ruins in play together.
When they created planeswalkers, they planned ahead that these storyline characters would get several cards and decided that two planeswalkers of the same type (usually their first name) cannot be in play together. However, NicolBolas, Venserof Urborg and Karnthe silver golemall exist both as a legendary creature and a planeswalker, and can be in play under both their identities.
It's also possible to send mana into the past to play certain spells from the Future Sight expansion. If you fail to send mana into the past on your next turn, you cease to exist. Clock Roaches indeed.
Tiger Versus Dragon: The ending of Alara block's storyline is this. Ajani Goldmane (a lionman, yes, but possessing tiger stripes) driven by rage and revenge, fights against Nicol Bolas, a time-tempered Dragon of renowned patience and planning.
Time Travel: How Vodalia wound up surviving at least to the time of the Phyrexian invasion, when every other Sarpadian empire got obliterated by this or that crisis.
To Be Lawful or Good: Gideon has a Heroic BSOD over this when Chandra reveals that the supposedly good organization he was a part of executed her entire village for harboring a pyromancer when she was a child.
More disturbing than the unknown is a distortion of the familiar.
Unscrupulous Hero: Urza. Destroying large landmasses, starting wars, and conducting a vast eugenics program just to breed a few warriors, for example.
Unwanted Rescue: After Starke sabotaged Vuel's coming-of-age ritual, Gerrard saved Vuel from death. Vuel resents him for it, for death would have been preferable to him after his failure. Starke stokes Vuel's hatred to make him Volrath, evincar of Rath.
Unwanted Spouse: Urza's wife, Kayla. He won her hand in marriage by winning a contest of strength with an automaton he built. He was more interested in the relics in her father's vault than her.
Villain Forgot to Level Grind: The skyships Weatherlight (the heroes) and Predator (the villains). When the two battle in Rath, the Weatherlight is outgunned and the heroes only escape through dumb luck. By the time of the Rathi Overlay in the Planeshift storyline, however, the Weatherlight had a more experienced crew and upgraded weaponry, and when the two skyships battled again, the Predator was thoroughly trounced.
Villainous Rescue: Geth rescues Glissa and Slobad in the first Mirrodin Cycle by dropping a huge swarm of nim zombies on Memnarch's head. Literally.
Violence Really Is the Answer: Karn was an actual pacifist for most of the time he spent with the Weatherlight and its crew, to such a point that the way Volrath tortured him was by locking him in a flowstone prison cell with a few dozen goblinoids and shifting the ground to make him kill them with nothing but his bulk. The trope appears in Invasion when Karn realizes that he remaining pacifist in the face of the Phyrexian invasion could cost him everyone he cares about, resulting in a Roaring Rampage of Revenge.
"Enough! If I must kill the guilty to save the innocent, then I will kill!"
Wham Episode: Oh no, the Phyrexians are back and they're attacking Mirrodin! Surely this invasion will be fought off - there's no way the story team would allow the good guys to make such a catastrophic failure! Right? Right?
Whatevermancy: Magic has more than its share of -mancers, both of the classical divination kind and the modern "control whatever it is" kind (some, like Retromancer, are a bit shaky on what their name actually is supposed to mean). Matt Cavotta Discusses Magic's -mancers here.
Many Planeswalkers go mad when they first awaken to their true potential. In more mortal matters, many mages in Dominaria's history have gone on rampages while drunk on their newly-developed creations or power sources.
Urza started slipping into this in his plans to defeat Phyrexia.
The World Is Always Doomed: Not always, but surprisingly often, and more so since the story got into the habit of moving on to a new world as soon as the current one stops being doomed.
In the Time Spiral block, the near-apocalypse that was the main storyline of the block was caused by so many near-apocalypses on the same world that time, space and magic were unraveling. When a planeswalker who sat out part of a previous interdimensional war returns to Dominaria, he tries to bring with him two continents that he had taken to another dimension with him.
Shadowmoor. It's the Mirror Universe of Lorwyn, and where that world represented a fairytale land, Shadowmoor represents the dark side of those tales. The fiery Flamekin have guttered into Cinders, the helpful Merfolk have become cruel pirates, and the tight-knit families of the Kithkin have become insular and xenophobic.
Grixis, one of the Shards of Alara, is a dark world, filled with undead and demons and slowly falling apart. Most of the magic in the plane is dependent on draining the life, blood, and memories from the living, and there isn't quite enough left... Arguably, all the Shards are this, as two of the colors of magic are gone from each, but Grixis is the most dystopian.
Rath, a plane created by Phyrexia to eventually be superimposed on Dominaria. The World Half Empty aspect was highlighted in Nemesis.
There's also an obscure factoid that one of the 1001 Rabiahs is just as bad as Phyrexia.
Unglued and Unhinged are about 50% puns (the other half is a mixture of cardpaper and in-jokes that only players of the game will get).
Unhinged had Donkey Folk, which only existed to make puns on "ass". There was Smart Ass, Dumb Ass, Fat Ass, Cheap Ass, Bad Ass, and City of Ass.
There are also the Clay Pigeon (a 1/1 flying bird that had an effect when thrown), the Rock Lobster (it wasn't a rock, and many take it for granite), the Paper Tiger (who burns bright and folds easily), and the Scissors Lizard (who has a lot of shear power).
Fowl Play turns things into chickens.
The Man of Measure is better at offense or defense depending on whether you're measured as taller or shorter than an opponent.
The Standing Army doesn't tap when it attacks, because they're always standing... but only as long as you are too.
Zendikar's Hat is that of adventure, this is caused in large part by 'The Roil' which reshapes the landscape of even entire continents on a regular, though unpredictable basis. Making maps nigh useless, and permanent settlements few and far between.
Year Inside, Hour Outside: In the novel Time Streams, a temporal explosion results in a group of Phyrexians getting stuck in a pocket of this kind of temporal anomaly, which makes them a much more dangerous threat to Urza and his allies and results in plenty of unusual strategies from both sides.
Your Universe or Mine?: After ascending, Elspeth wanders the Blind Eternities looking for a new home. She finds it in Bant, which is everything she could have ever hoped for. When the inevitable apocalypse comes to Bant, she decides to leave the plane thinking that it's for the best if they learn to fend for themselves rather than rely on her considerable power.
Grixis. Given that there are a good chunk of zombies on the plane, and everything is going to hell, it certainly fits the end trope. A bit more Romero in that the zombies aren't the source of the plane being messed up, but that magic is out of balance so that Black Magic overtakes everything and regrowth is no longer an option.