The modern era is chock full of crime solving shows, it's a genre by itself. Unfortunately the massive number of these types of shows has made it difficult to a new one to stand out or get noticed amongst the rest. Good character development, interesting plots, and occasional humor are still great ways to keep an audience, but none of that means anything if you can't convince an audience that your show is unique enough to be worth giving a try.
To address the difficulty of drawing audience attention away from so many competing shows recent additions to the genre tend to use a specific gimmick, something memorable that makes them stand out as a unique take on a well defined genre. They may fights crime with Obsessive Compulsiveness, or fights crime with lawyers. Almost anything can be used, so long as it's unique. Often these gimmicks don't even make sense, and realistically the reason we don't see them in most crime shows is they don't work nearly as well as the series would like you to believe. Still, as long as it helps your show stand out amongst all the rests it's a good gimmick.
A side effect of these types of shows is the need to justify the gimmick and the premise. This can result in making the gimmick far more effective at solving crimes then it should be possible. It's also quite common to imply the protagonist has some unique gift that allows him alone to fight crime with his gimmick. It's not unheard of for protagonists to be some form of Bunny-Ears Lawyer with bizarre or annoying quirks that are tolerated only because they are so gifted at solving crimes. A Hand Wave about how the main characters are assigned to the "odd cases" which require their gimmick in order to be solved is sometimes tossed in.
These shows often have to show the protagonists investigating and capturing criminals, which can lead to implausible situations of police tolerating civilians being more involved in the crime fighting then any precinct would allow in real life. In shows that feature teams of scientists/experts fighting crime they will often be allowed to interrogate suspects and participate in arrests despite this not being their actual job! These issues are Necessary Weasel, as realistic show would prevent out protagonist from being involved in the most interesting phases of crime investigation.
Remember Tropes Are Not Bad, and just because a show relies on a gimmick to help it stand out does not prevent it from being a great show. While the gimmick may draw original viewers it's the show's writing and characters that will decide rather it lasts. These shows can provide some of the most memorable crime fighters and great plot-lines if done well. Though, as with all fiction, Sturgeon's Law still applies.
One of the earliest examples and Trope Codifier is likely CSI, which fights crime with forensic science! The show grew immensely popular, and also gets credit for having one of the most plausible gimmicks of all of these types of shows, as it's the only one that *is* regularly used to solve crimes.
Compare Interdisciplinary Sleuth (which is mostly, well, sleuths with an odd skill set, while this trope is more of a catch-all "fight crime with gimmick" list), Unbelievable Source Plot (where the "x" is something that provides the crime-fighter with information, is impossible to believe by the "real world" definition of the setting, and said fighter needs to both prevent the crime and make sure that whoever helps him doing so doesn't thinks he's crazy (or worse yet, that he is the cause of it)), Crimefighting with Cash (where the defining "gimmick" is that the character is a Fiction 500 member (or at least stinking rich) and uses this cash to pay off trouble), Improbable Weapon User and Improvised Weapon (both of which encompass a "gimmick" that is an unusual device taken into battle as part of the character's crime-fighting).
- In the cyberpunk-ish world of Un-Go, the poor publicity Yuuki "Defeated Detective" Shinjurou unravels conspiracies. An ace up his sleeve is his assistant, a supernatural shakily-tamed souleater with a power to compel a given person to answer one question Yuuki asks, fully and truthfully.
- In the Ghost in the Shell series, Public Security Section 9 fights crime by using electronic warfare with a mix of detective work, espionage, counterterrorism, black ops and sometimes, assassination of high value targets when necessary.
- The show has police forces fighting against criminals and terrorists with the deployment of mechs called Patrol Labors or "Patlabors".
- The Next Generation -Patlabor- movies (which are a sequel to the show) has them fighting criminals and terrorists with Patlabors, but on a reduced budget due to the economic crisis in 2008.
- Dominion Tank Police. The police force fights crime with tanks (justified in that the city is a futuristic Wretched Hive of the highest caliber), with the protagonist using a Mini-Mecha version of said tanks.
- Appleseed has a special police counter-terrorism unit made up of active police officers and mercenaries to take on criminals and terrorists in Olympus with the occasional deployment overseas with or without consent from the sovereign government of the day.
- Jiraishin has detectives investigating/fighting crime throughout Tokyo (with the occasional trip to other parts of Japan or overseas) through detective work, sheer willpower and determination to solve the case and when all else fails, the use of their sidearm to kill the suspect before things get too complicated.
- The Case Files of Yakushiji Ryoko involves Superintendent Yakushiji Ryoko investigating paranormal crimes committed by (most of the times) criminals, terrorists or rogue police/military teams by using Tokyo Metropolitan Police resources, including her subordinate Assistant Inspector Junichiro Izumida, or by using the manpower/resources of a Japanese Private Security Company note established by her father called JACES alongside her French ninja maids.
- Blake and Mortimer has Captain Francis Blake and Professor Philip Mortimer fight crime/terrorism by using detective work, espionage, science and their contacts with Western/pro-Western governments/law enforcement/military/law enforcement agencies if overt/covert support is needed.
- In the original comic version of Human Target, which is done in the 1992 television version by ABC, Christopher Chance helps his clients take on criminal/terrorist threats against them by using special facemask technology in order to impersonate them and draw out the bad guys out. In the 2010 television version produced by FOX, Chance instead puts himself alongside his client/s so that he or his associates can take down the threat before it's too late.
- Kara no Kyoukai has an anti-supernatural detective agency called the Garan no Do. Led by Touko Aozaki, who is known sorceress in the underworld, she leads the agency to help law enforcement solve cases of supernatural origin when police investigations lead nowhere by offering her Occult Detective assistance.
- Persona x Detective NAOTO has Naoto fighting crime with detective work coupled with assistance from her persona powers and a sentient Kirijo Group-made anti-Shadow android named Genesis aka Sousei Kurogami.
- Net Force and Net Force Explorers has the FBI's anti-cybercrime division called Net Force, which uses government-employed hackers to take down criminal and terrorist plots. They also get assistance from the FBI's other resources and then, from the US Marines after they take control of the agency. However, NF agents conduct a black op to destroy the residence of a known assassin so that said assassin will take out the one who hired him.
- The Rainbow Six novel/video game series involves the deployment of RAINBOW, a multinational special forces unit made up of trained special forces personnel from elite law enforcement and military units sent in to fight criminals and terrorists when all options fail to resolve the situation.
- Monk. Fights crime with amazing Sherlock Scan abilities born from immense Obsessive Compulsiveness.
- Bones. Fights crime through forensic anthropology (as in, studying bones left behind by badly decayed and/or damaged bodies). Some cases are old, some are rather recent.
- NUMB3RS. Fights crime with mathematics (bundled into that includes game theory to analyze the perp's actions and predicting moves, advanced hacking techniques, and so on).
- Lie to Me. Fights crime with human lie detectors, which consult with law enforcement agencies that do the regular legwork.
- Endgame. An Amateur Sleuth that fights crime with chess! Though it's less fighting crime using chess as "fights crime, using knowledge of the human condition that he learnt from playing chess... also there's chess".
- CSI and its off-shoots: Fights crime with forensic science (which occasionally borders on Applied Phlebotinum in its accuracy). ''CSI: Cyber" (the final show on the franchise) expanded this to the field of fighting cyber-crime.
- Law & Order. One of the first shows that focused equally both on police procedure and court procedure (essentially, fights crime with lawyers), though this one is debatable, and is more of a proto example before the gimmick shows went to the extremes they go to now.
- Psych. A Brilliant, but Lazy Amateur Sleuth fights crime with Sherlock Scan (but that he pretends are psychic) abilities.
- The Mentalist. Fights crime with advanced Sherlock Scan (which some folks believe are psychic) abilities, a Manipulative Bastard attitude and occasionally weaponized JerkAssery.
- Castle. Fights crime with large amounts of Genre Savvy born from being a veteran mystery writer. And occasional favor to ask to someone who can provide assistance.
- Murder, She Wrote: Little Old Lady Investigates, using Genre Savvy obtained from being a best-selling mystery writer. Jessica Fletcher did it long before Richard Castle.
- And beating the both of them by a few decades, we have Peter Wyngarde's Jason King (from Department S and his eponymous off-shoot show), who used his knowledge as a mystery writer (and occasional exploitation of his fame to open doors) to solve mysteries.
- Criminal Minds. FBI Agents (all of them an example of The Profiler) fight crime (mostly Serial Killers, but sometimes other types of crimes such as kidnapping and espionage) with (impressively accurate) profiling skills and the expertise to weaponize them.
- Cold Case. A specialized police squad fights crimes that are many years old, using modern techniques that weren't available on the time of the cases' opening and sheer determination.
- Dexter. A moonlighting Serial-Killer Killer (that works for the Miami-Dade Police as a forensic investigator) solves crime by knowing exactly how his victims think and giving them a taste of their own medicine before killing them.
- Crossing Jordan: In the first season and a half or so, Jordan fought crime as a coroner with the help of (a) her coroner abilities and (b) her imagination, putting herself in the shoes of the victim and figuring out what happened. After the first season and a half Jordan turned into a CSI clone, fighting crime with forensic science.
- Pushing Daisies: Ned fights crime by bringing the dead back to life for 1 minute in order to ask who killed them.
- Unforgettable: A New York City detective (and her ex, also a detective with which she still has chemistry) fights crime with a Photographic Memory.
- Intelligence (2014): An agent of the US Government (and his bodyguard/partner) fight threats to the United States, with said agent having chip implanted in his head that gives him wireless access to the Government's Magical Databases and makes him an uber-hacker.
- Miami Vice: Cops that fought crime by going undercover (Only in Miami during The '80s, in all its pastel-colored, borderline Place Worse Than Death glory). The series was loaded with Gray and Black Morality and was one of the first to heavily feature the characters going through Pyrrhic Victory after Pyrrhic Victory (on their best days) to show that police work is hard and Drugs Are Bad.
- 21 Jump Street featured a "radical" undercover cop program that placed cops Older Than They Look back on the classrooms, providing a combination of Teen Drama and cop drama.
- Knight Rider: A member of a Heroes "R" Us uses a computerised, talking, virtually indestructible car Robot Buddy to fight crime.
- The Mod Squad featured a trio of teenage Boxed Crooks that did undercover work (without guns, badges or official authority, informing about or knocking out the bad guys for their cop handler to arrest) in order to earn their freedom.
- F/X: The Series: Rollie Tyler, his crew and the policemen they helped fought crime using typical investigation and a variety of gadgets (such as Hollywood-caliber Latex Perfection, a dog-like Robot Buddy and so on) that were invented by Rollie for various movies that he films throughout the show (and pretty often set up a Chekhov's Gun by demonstrating an effect on the movie that would be used on the episode later).
- Person of Interest: Group of people fights crime by capturing or saving people (using targets provided to them by an Artificial Intelligence that is the latest in Sinister Surveillance) using their various skills as experienced spies, police officers and being the Playful Hacker Magnificent Bastard that created the Artificial Intelligence.
- Due South: An Odd Couple of policemen (one a Chicago detective, the other a Canadian Mountie) fights crime with Chicago street smarts and Canada nice (and other odd abilities). And a half-wolf.
- Various shows from The '80s and The '90s (such as Airwolf, Blue Thunder, Viper, Street Hawk and the aforementioned Knight Rider) followed a formula of the heroes fighting crime with an advanced vehicle (like a Cool Car, Cool Bike or Cool Plane) providing them with means to detect said crime and severe firepower.
- Forever Knight: Vampire fights crime as a policeman (on the night shift, obviously), using vampire powers and skills obtained from his long life. This series was the Trope Maker for the Vampire Detective genre (comprising shows like Angel, Moonlight and the Lifetime channel's Blood Ties), at least on television.
- Stalker has police officers from the LAPD's Threat Assessment Unit face off against stalkers with investigations into their MOs (coupled with Detective Larsen's Sherlock Scan and Genre Savvy).
- Tokusou Sentai Dekaranger and its English counterpart, Power Rangers S.P.D., involves police officers fighting against alien-based crimes on Earth by using Space Police-made technology, including morphers and mechs when they need to face off against huge alien monsters/robots. The former tangles with an intergalactic arms dealer while the latter deals with an intergalatic alien empire who works with an arms dealer.
- In Life L.A.P.D. Detective Charlie Crews is a millionaire because he sued the city after he was falsely conviceted of murder; but other than having a Cool Car his money didn't really enter into his detecting. Also he maintains a (literal) Zen Survivor mentality after his stay in prison nearly drove him insane, and this mindset provides him with a powerful tool for manipulation.
- Like Life, Burke's Law features a police detective that happened to be rich (and long before Life did, too). Aside from driving around in a limo (and the limo's driver being one of his sidekicks), it also didn't influenced much (if any) into his detecting, although it did gave him some access into the lavish lifestyle of the rich and famous of L.A. so he could investigate them when needed.
- Flashpoint involves a special response unit called the Strategic Response Unit that tries to resolve hostile situations by confronting armed suspects (and sometimes against their own) through negotiations and when all else fails, use deadly force.
- The Listener involves a Toronto paramedic named Toby Logan, who gains psychic powers to listen to people's inner thoughts. He uses his powers to help the Toronto Police Service and the Royal Canadian Mounted Police to solve crimes in Toronto.
- Republic of Doyle involves the Doyle and Doyle detective agency as Jake and Malachy Doyle investigate crimes perpetrated throughout Newfoundland and Labrador by foot chases, detective investigation and using their allies in the Royal Newfoundland Constabulary to solve their cases. It also involves Jake's GTO when car chases are in the mix.
- Cracked involves an ex-operator of the TPS's Emergency Task Force as he is transferred to the Psych Crimes and Crisis Unit as he and the other officers in the unit investigate crimes in the Greater Toronto Area by examining the emotional and mental health of the suspects, victims and witnesses.
- Leverage involves an ex-insurance detective when he forms a team of ex-convicts as they work together to help out victims by taking on criminals who use their power and influence on the American justice system to ensure that they stay free.
- The Blacklist involves the FBI getting help from a publicly known criminal and information broker who helps them arrest or hunt down criminals, assassins, terrorists and spies through his list called The Blacklist.
- Kamen Rider series
- Kamen Rider Kuuga has the Tokyo Metropolitan Police Department's Science Police Force formed to investigate and take down Grongis involved in crimes and terror throughout the Greater Tokyo Area.
- Kamen Rider Agito has the TMPD create a Kamen Rider-based Powered Armor called the Generation 3 suit used by police officer Makoto Hikawa to take on The Lords.
- Kamen Rider Drive has detective Shinnosuke Tomari, who changes into Kamen Rider Drive when the TMPD's Special Circumstances and Incidents Investigation Division (informally known as the Special Investigations Unit) is called in to solve crimes and terrorism involving Roidmudes, murderous androids that appeared during an incident known as the "Global Freeze Incident".
- The Metal Heroes franchise in Japan involves a variety of characters, most of them being police officers or police androids/cyborgs, fight crime and terrorism in Japan by using highly advanced weapons and equipment by either being a Henshin Hero, having Powered Armor or by just being a Cyborg or being Ridiculously Human Robots.
- Kaiketsu Zubat has Detective Ken Hayakawa take on a terrorist group called Dakker by becoming a vigilante when he dons the Zubasuit.
- K-tai Investigator 7 has Keita working with a Japanese mobile phone provider called ANCHOR, which covertly fights crime and terrorism by using a black ops intelligence organization called Under ANCHOR to hunt down suspects through company resources alongside the internet and mobile phones that have sentient AIs to assist UA operatives.
- Forever: Medical examiner Henry Morgan fights crime with 200 years of experience and a mysterious ability to keep coming back when he dies.
- On the same vein as the above show (but much earlier), New Amsterdam followed the adventures of an immortal that had become a cop and used the wide variety of miscellaneous skills and information that he had accumulated over his long life to solve the cases.
- Columbo: Lieutenant Columbo fights crime with an immensely powerful application of Obfuscating Stupidity (to the point he is considered by some the Trope Codifier of "seemingly bumbling but incredibly adept'' detectives in television).
- John Doe followed the adventures of the titular heroic amnesiac, who had somehow become a living Omniscient Database and searched for the reasons why this happened while helping the Seattle Police Department.
- Devil Summoner series. The various Devil Summoner games (Devil Summoner and the two Raidou Kuzunoha games Raidou Kuzunoha vs. The Soulless Army and Raidou Kuzunoha vs. King Abaddon) involve detectives from the 1930s to modern times using detective work with consultation from allies/informants who dabble in the occult to solve criminal cases. They also summon demons to battle their enemies whenever the paranormal is involved.
- The Hayarigami games consists of officers investigating seemingly paranormal-based crimes by relying on old-school investigations and interrogation of suspects and witnesses while consulting with specialists to determine if the case is done by a criminal using urban myth to cover it up or if the paranormal is involved.
- Scooby-Doo (and other shows that followed it, like Jabberjaw, The Funky Phantom, The Amazing Chan and the Chan Clan, Speed Buggy, Josie and the Pussycats, etc.) followed (almost) the same formula of Amateur Sleuth Meddling Kids (and non-human sidekick of some sort) dealing with Scooby Doo Hoaxes and Stupid Crooks. Although sometimes they did nothing but being the Kid-Appeal Character.
- Kim Possible has Kim Possible with her friends, Ron Stoppable and Wade, take on criminals by working as a covert anti-crime team whenever they're not busy with school.
- The cartoon version of Martin Mystery involves agents fighting against paranormal/alien crime by using alien-made tech and investigations to determine if the perpetrator is something paranormal/alien, someone trying to make it look like one or if someone is trying to take advantage of the former.
- Totally Spies! has a covert law enforcement agency called WOOHP that fights criminals/terrorists by using female teenagers who double as WOOHP black ops agents in their spare time away from their high school/college lives.
- Young Justice has the Justice League fight criminals/terrorists by assembling their sidekicks/proteges into a team that operates against them in a black ops capacity so that the League can use plausible deniability in case of a situation that tries to link an event to them.
- Inversely parodied on a quick joke in Futurama: TV shows of the 31st Century have run the "unusual gimmick" plot so far into the ground that one show, The Finder-Outer, actually manages to draw attention by having its main character having nothing to help him solve cases.