Author Appeal: Snowdrop for Max; since the Brony Rappers React episode where he watched it, he seems to have taken a great liking to her, even stating that she's his favorite pony despite not being a canon character. It doesn't start to become this trope until this song, when he starts his verse off with "This is for Snowdrop" despite the song being completely unrelated to her or ponies in general.
He also has a shrine dedicated to Snowdrop in New Letropolis, as shown in episode 9 of The Drawing Board.
Fallout: Equestria references have also begun cropping up, such as the "Know Your Myths" episode of Cutie Mark Laboratories being filled with various pieces of Littlepip fanart.
Boastful Rap: His raps normally avert this; so far, the only times he's played this trope straight are when the rap is boasting for a fictional character (such as Luigi for his Luigi's Mansion rap) or a contest entry of sorts.
He even inverts this trope with his rap Asperger's Syndrome.
Seems to have started playing this straight, though he keeps it moderate and doesn't go to nearly the same extent as typical rappers.
Call Back: In "Atomizer Redemption Popdemption", he references a previous rap he did that was a cover of the original Atomizernote "Atomizer" was a rap done by Ibeabronyrapper, and "Atomizer Redemption" was a remake of said rap; Max did covers of both raps in two spots.
Ohai, I'm SAWme Guy has callbacks to loads of Max's let's plays and other videos. There's references to Tekkit, The Drawing Board, Skyward Sword, and even Max's obsession with Snowdrop. Of course, they're all relevant to some sort of "test".
Canada, Eh?: Max, Peter, and Schuyler are all Canadian. None of the other guests so far are, though.
Surprisingly, Max actually does say "eh" rather often, but not actually to cap off a question like people imagine; he says it more as a statement whenever he has nothing better to say, kind of like a "Whatever".
Casual Danger Dialog: In Ohai, I'm SAWme Guy (the 2013 Halloween Special), Max's response to everything going on is a mixture of confusion, disgust, and his typical Deadpan Snarker attitude - even when his life is on the line - rather than outright fear. Until the end, anyway.
Cloud Cuckoo Lander: Peter. Also Max, to a lesser extent, though this shows more when he's with Zero or Schuyler.
Cursed with Awesome: He's been known to utilize his insomnia as a way to get editing done overnight without getting tired.
Deadpan Snarker: Everyone to appear so far has at least a few moments of this, but Max, Schuyler, and Zero are the main examples.
Max's snarkiness noticeably increases when he's on his own in his let's plays.
Don't Try This at Home: Max makes it very clear that viewers shouldn't attempt the Batman voice he does (formerly known as just "the demonic voice"), let alone sing songs in it. Just singing songs that are a minute or two long makes his throat very sore, and also makes him lightheaded from lack of air - apparently, doing the voice uses more air than you'd think.
Drunken Master: More like Tired Master, though. When Max is sleep-deprived, he appears to actually be more intelligent than normal (though after a while this fades).
This intelligence actually stems from being easily distracted due to being tired; his brain goes off on weird thoughts while he's working, and so he works absentmindedly on tedious tasks while his brain is thinking random things, often coming across ideas or theories that actually work and make sense.
Early-Installment Weirdness: His videos used to be in very low quality at 240p. After a bit he started uploading in 480p, which was somewhat better. Recently he's finally made the jump to HD, with 720p for most videos and 1080p for his music.
Back in his first couple years on YouTube, he used to make Machinima primarily using Super Mario 64 and Super Smash Bros. Brawl. He eventually switched over to let's playing and deleted his machinima videos, but he left up one video - a Garry's Mod machinima video that is currently the oldest one on his channel - solely because it's his most popular video so far.
Hilarious Outtakes: He released a blooper reel from season one of Classification: Awesome, featuring him stumbling over his words a lot.
He also released bloopers from ALICORN TWILIGHT SPARKLE.avi, which was nothing but over a minute of footage of him jumping off a porch for the Driven to Suicide scene. Funnier than it sounds, especially considering on two occasions he fails the jump completely.
Hitler Cam: Uses this sort of angle in his BRINGIN IT RAW music video.
Inverted when he uses a facecam in his visual novel let's plays, as he has the camera looking down at him.
Iconic Outfit: Whenever he is actually shown in his videos or video thumbnails, he wears a dark green hat and has a flash drive around his neck. He also usually wears a hoodie of some sort, recently a dark blue one. This is averted if he has to wear a specific costume for a video, such as in ERBParodies, and occasionally he won't bother with one part of the outfit, such as only wearing the hat in his ice bucket challenge.
Originally, the dark green hat was a Creeper face hat, and then later an Ellis trucker cap. His hoodie also was originally an asymmetrical blue and yellow hoodie with one black-and-white sleeve, then a (once again) Creeper hoodie. Essentially, his outfit tends to change in terms of appearance occasionally, but it always keeps the same "hoodie and hat" theme.
I Have Many Names: RLYoshi for let's plays (and most other stuff), Pop Filter for music, and his ponysona Winter Solstice. There's also his real name, of course.
His "William Shatner Syndrome" doesn't come up nearly as often as he seems to think it does.
The Insomniac: Max used to record a lot while sleep-deprived, which made him a lot calmer in terms of commentary but a lot more erratic in terms of his actions, especially in games. He still has insomnia, but doesn't record while exhausted as often anymore.
Made of Iron: In "Jumping Off A Porch" - the blooper reel for a live action short he did - he jumps off his back porch several times (and there were apparently even more attempts that weren't put in the blooper reel). Note that his porch seems to be ten feet off the ground note the rail at least is; he jumps from the rail and, while he appears to have his fall cushioned by snow, he states at one point that it's actually ice he's landing on. He still appears just fine.
He has stated a couple of times that he has a natural resistance to pain.
Mean Character, Nice Actor: Okay, he isn't exactly a character, but Max is often portrayed as being incompetent and a jerk in his let's plays. In real life, however, he's much nicer, even if he retains his snarkiness. For example, see this Tumblr post.
Motor Mouth: Max can talk damn fast when he wants. Zero and Peter can as well.
No Indoor Voice: Max sometimes speaks loudly, even when there's nothing big happening.
Non Sequitur: Peter lets these off all the time. Usually they involve pineapples, the colour purple, or both.
Not So Stoic: Schuyler manages to crack a few jokes, despite being emotionless most of the time.
Obfuscating Stupidity: Some may think he's doing this in his videos, given how he has shown surprising sanity and intelligence at other moments (even if he stays sarcastic). For example, his stance on Equestria Girls as seen in the first episode of Brony Rappers Reactnote He remains calm and neutral, using simple logic to tear apart any of the arguments towards the movie that are brought up, such as how the character designs may lead to young girls trying to "slim down" and going anorexic, and his Tranquil Fury approach to a host of the BronyCon event Whose Line is it Anypony? being unfairly fired note He posted a recounting of the events in an unbiased manner, kept his own opinion on the sequence of events leading to the problem secret, and subtly asked followers to help try and get the host rehired. Then there's DEATH BATTLE: Equestria...
Basically, when outside of his gaming videos, Max is a lot more intelligent.
Oh Crap! There Are Fanfics of Us...: Someone sent Max a shipping (later clarified as just friendshipping, though) fanfic between himself and Peter. Max's response was that he didn't know whether to laugh or groan.
Max, Peter, and Zero often reference the idea of shipfics being written about them if any sexual references are made. Oftentimes, said references are begging people not to write them.
One of Us: Max and Schuyler are both tropers, and Max loves referencing tropes whenever he can.
Serial Escalation: How he got sixteen pet wolves in The Drawing Board. He tamed a single wolf while building railways, then later decided to spawn a second one so he could be symmetrical and have one on either side of his bed. He then accidentally gave them enough meat to make them mate and have a third wolf; at that point, he just decided to spawn three more and have one for every colour of the rainbow. Then - while filming Gargantuan TNT, nonetheless - he again accidentally gives two wolves enough meat for them to mate, and he wound up with a seventh wolf. He apparently decided offscreen to just spawn nine more, and have one wolf for every possible collar colour.
Shrine to the Fallen: Episode 9 of The Drawing Board reveals that there's one somewhat hidden behind a hill near New Letropolis, heavily implied to be dedicated to Snowdrop.
Spiritual Successor: N.O.V.A. appears to be one of Classification: Awesome. It retains various review characteristics, but has a few removals and additions. It loses the special intro, snarky comments, specific update schedule, and final score; but it also gains gameplay footage, talk of different strategies within the game, and overall an increase in quality and production value. And, just like its predecessor, it was unceremoniously canned.
Stealth Pun: In "Ohai, I'm SAWme Guy", the Jigsaw expy who's actually Zero tells Max "I shouldn't have to try forcing you to keep moving." The next thing Max stumbles upon? A giant Triforce.
Trademark Favorite Food: Max seems to have a thing for pizza, as shown when Peter brings up in one Skyward Sword episode how they always eat pizza for lunch whenever he comes over to record.
He and Peter also like to drink a fruit juice called Five Alive. Max states that it apparently acts like coffee to him and gives him energy, while Peter just seems to like the taste.
Unusual Euphemism: He has recently begun censoring himself by replacing words like "fuck" with other words. He says "son of a Changeling" instead of "son of a bitch", and says "fuck" and "shit" backwards ("cuff" and "tish" respectively). He eventually stopped caring about this and now just swears normally when he feels the need to at all.
In ERBParodies as the Enderman: "Come lick my Ender Pearls!"
Verbal Tic: Max uses "Eh" as a replacement for words like "Whatever" or "Good point".
He strictly says "Alrighty" instead of anything similar to "okay".
He adds "...kinda thing" to the end of sentences if he's sort of just rambling on or not entirely sure what he's saying, such as in his update vlogs.
Workaholic: Several let's plays at once, plus (for a time) the Super Vexation Saga. Music, animations, short films, fan fiction, and scientific theories. And he's still got other stuff planned.
He's stated that he spends every waking moment working or planning for when he can work again.
Younger than They Look: His voice and appearance give the impression that he's a lot older than he really is. He frequently gets mistaken for being over 20, even in person, when he's only about 18.
Peter gets hit with this similarly, thanks to being so tall.