Smoke Choked

The sole mini boss of Blaze Heatnix's stage from Mega Man X6
By Ahuron

The first phase of the Sigma fight from Mega Man X5. Comes with many variants of the Fake Zero intro from Mega Man X2
By Ahuron
 

Mega Man X in his fully powered state from Mega Man X4
By Ahuron
 

This is a source accurate version of Mega Man in Mega Man IV, except he's tiny.
By Ahuron

This version of Conan was released for April Fool's Day 2018, and thus he is a joke character. As long as the opponent can be grabbed, his only attack is to catch the opponent red-handed with a crime and pin it on them. This OHKOs said opponent.
Until YU-TOHARU finishes the legitimate version of Conan, which they are working on, this remains the only version available.
By YU-TOHARU
 

The Panzer IV, more specifically the Ausf.F2 model, was one of the battle tanks used by the Nazis during World War II. In Girls und Panzer, on the other hand, this tank is piloted by a group of adolescent girls in the Anglerfish Team. This team consists of Miho Nishizumi, Saori Takebe, Hana Isuzu and Yukari Akiyama, and all four of them converse to one another while the tank is being controlled.
Naturally, this makes the Panzer IV a very unconventional character, since it is literally a tank.
By YU-TOHARU
 

This a superdeformed (SD) version of Jiban from The Mobile Cop Jiban. This version is taken from SD Hero Soukessen: Taose! Aku no Gundan, a Japan-exclusive platformer game focused on Ultraman, Kamen Rider, Metal Hero and Gundam. Jiban is one of the three representatives of the Metal Heroes franchise, alongside Shaider and Metalder.
By YU-TOHARU

Voodoo Spike himself, hailing from one of the Ranma ½ fighting games, Ranma ½: Hard Battle. If I am not mistaken, this version of Gosunkugi is designed to be source accurate, much like the creator's own Pantyhose Taro.
By YU-TOHARU

Take the self-harming assists of regular Genbaneko, and make them constantly covering up the screen, and you get Genbaneko-Chaos
By the Nijikaku Team, edited by SSBK65
 

One of the newest characters from Nijikaku
Based on a Futaba Channel meme from 2018.  Like Mukuro, he has a tendency to unleash assists that will harm both the opponent and himself.  However, unlike Mukuro, assists will come out automatically.  Be wary of the spinning cat head in the corner.  When it turns red, watch for the exclamation point to avoid getting hit by your own attack!
By the Nijikaku team, labelled as "man"
 

You sit on a throne of LIES
Based on a SiIvaGunner rip, this character was made as an inside-joke to the community of people that make YTPs in the same style as the rip.  However, the joke fell flat due to how a lot of those videos are now lost media, so this guy got released in July of 2021.
By lau gaming.соm

A dominatrix kumiho (nine-tailed fox), and she's another lovely character from this wonderful author!
By Moku

Yami was only put in Tatsunoko Vs. Capcom so Capcom could have a multi-phased boss, which makes its ball form look incredibly stupid. This is an adaptation of the first phase, and the first phase only.
By BoyBoyz
 

Based on CHOUJIN's Perfect Cell, transformed into a masterwork by Turbo
Based on this video: 
 
Showcase video, compared to the original Perfect Cell:
 

The home stage of Psycrow from the Earthworm Jim series
By Spat856+Dummycorps

An original stage based on the Winter season
By Spat856

An unfinished beta version of Rarity, only released on Spat856's website.
By Spat856, DummyCorps, Someguy

A patch that provides different hyper portraits for Morrigan_D9x7
By Spat856

If you think Ghetto Warmachine's yammering is annoying and loud, download this patch to make him a bit quieter.
By Spat856

This version of Skullman fights solely in his X-form, the form that fights like a regular character. You're welcome.
By aokmaniac13+The_None, edited by Spat856
 

Not the earliest cartoon character, but definitely the most famous of the pre-30s era of cartoons.  He's been in cartoons since 1919, back when he was named "Master Tom", and went on to star in many shorts and TV shows up to the early 2000s.  This version of Felix is based on his NES game, which came out a few years after his failure of a motion picture, and a few years before his best series, The Twisted Tales of Felix the Cat.
By RoySquadRocks
 
 

Just your typical Reisen. Plays like your typical Touhou character.
By Muirtower
 

This version of Konata hails from Lucky Fighter II, a Lucky Star version of Super Gem Fighters Mini Mix aka Pocket Fighter. She plays pretty accurate to her source game.
By Muirtower
 

Like the original stage, you must guide your character (supported by Tails's biplane) to the end of the stage while avoiding flying badniks. Collect rings along the way to avoid being knocked out by the badniks. The stage is more difficult to play when playing as a large character.
By Phantom.of.the.Server
 

The objective of Catwalk is to hit the buttons that appear on screen at the right time; that being when the buttons overlap the green line at the top of the screen. If the player misses a button press or presses the wrong button, they will lose some life. Life can be slowly regained by hitting a string of buttons, known as a "chain" in-game (not to be confused with chain attacks). The player must survive for a given period of time as indicated by the "TIME" bar at the top of the screen; this defaults to 60 seconds.
Due to technical limitations, Catwalk's note chart does not map to any particular song or stage, nor does the character come with music. This also means the chart's length is determined by a timer rather than the length of a given song, and is charted semi-procedurally. The chart's speed starts at a default rate, but increases for every chain of 50 notes successfully hit. If a player breaks their chain, the speed reverts back to the default.
Catwalk has a configuration file, CONFIG.txt, which contains a few options that can be adjusted to make the game easier or harder. BASE SPEED is the default speed of the chart, Use X Y Z toggles whether or not to include the X, Y, or Z buttons in the chart, PENALTIES ON/OFF toggles whether the player should be punished for pressing the wrong button, ARROWS POSITION aligns the directional button icons to the left-hand side of the chart, and KEY LIMIT limits the number of notes that can appear simultaneously.
By Phantom.of.the.Server