Remember that I'm doing this more for fun than for debate or power scaling lol

Both are powerful characters who were enlisted at a young age due to their powers (Songbird being enlisted by the FIA and Ava being enlisted by Shield), both went rogue to find a cure, both got “enlisted” by someone who’s “morally grey” (Hansen for Songbird and Valentina Allegra de Fontaine for Ava)

They were both also frequently used as weapons (Alex mentions that Songbird is a walking WMD and Ava tells Antman that Shield used her as a walking secret weapon), both were dying from being forced to frequently use their powers, both were frequently lied to (they were both promised a cure but had it held over their heads to get them to cooperate)

“For Myers, the NUSA... I'm just another weapon in their arsenal. A tool for reachin' beyond the Blackwall. And weapons and tools? They don't get to make decisions or choose to retire.” - Songbird

“They weaponized me. I stole for them. Spied for them. I killed for them. And in exchange for my soul... they were going to cure me. They lied.” - Ghost

Main Theme: Quick-to-anger teenager girls who serve as the latest in a long line of Asian-inspired heroes going way back to ancient times, who go on a journey across four distinct fantasy realms, each one granting them a different power set, while accompanied by a group of their three best friends, consisting of one other girl and two boys, while facing off against both modern and ancient evils coming from this world and from another beyond.

Meta Theme: Protagonists of spin-off/sequel series from iconic works of children’s entertainment (Mônica Adventures being a spin-off/sequel of the original Mônica’s Gang, and Legend of Korra being a spin-off/sequel of the Last Airbender), somewhat aimed at more mature audiences than the original work (Mônica Adventures is explicitly made for teenagers, rather than children like the original, and Legend of Korra is known for being more graphic than the original, with characters being shown to die on-screen), which are American works (Mônica Adventures being a Brazilian comic, and Legend of Korra being an American cartoon) heavily inspired by Asian forms of entertainment (Mônica Adventures being made to resemble a manga, and Legend of Korra being made to resemble an anime), which is also reflected in the world of the work raving a lot of Asians influence (Mônica Adventures having multiple characters with Japanese names and making use of many tropes that are common in manga, and Legend of Korra having the Four Nations each be inspired by a different Asian culture and making use of many tropes that are common in anime).

Connections:

• Teenager girls who serve as the latest in a long line of Asian-inspired heroes going way back to ancient times (Mônica being the next in line to be one of the Four Heroes of the Emperor, which were created by Emperor Go-Yōzei of Japan in the Edo Period to protect the Earth from mythological threats, and Korra being the latest reincarnation of the Avatar, which was created by Raava in ancient times to keep the balance between the Material World and the Spiritual World).
• Specifically carry the responsibility of following up what was considered one of the greatest of said heroes (Luísa for Mônica, and Aang for Korra) and who they share a personal link towards (Luísa being Mônica’s mother, and Aang being the father of Tenzin who is Korra’s Airbending master).
• The title of said line of heroes is passed when the previous hero becomes unavailable (The Four Heroes of the Emperor lose their memories of even being heroes when they pass the mantle to the next generation, allowing them to live the rest of their lives as normal people, and the Avatar reincarnates after death, allowing their spirits to pass on and be at peace unless called to guide the current Avatar).
• Said heroic title is formed by the combination of the greatest power of four different nations (Emperor Go-Yōzei formed the Four Heroes of the Emperor by going to the leaders of France, Spain, Portugal, and England, and asking for their greatest warrior to form the team, and the Avatar was created when Raava agreed to carry the Four Elements that would later form the Four Nations, Water, Earth, Fire, and Air, and then fuse with Wan to become the first Avatar).
• Known to be quick to anger, with this being a major character flaw that harms them at some point in the story (Mônica’s anger being the main thing represented in Akanin, her ID Monster that personifies all of the raw and uncontrollable aspects of her personality, and Korra’s anger and impatience being what initially blocks her from using Airbending, due to it requiring her to not force her way through and be a leaf in the wind).
• End up overcoming said weakness in a climactic battle (Mônica managing to control her anger and overcome Akanin, making her ID Monster shrink into a weaker form that she could trap into an ID Card, and Korra managing to Airbend during the final battle against Amon after having her Chi Path to Bend the other three Elements blocked).
• Said enemy affected them on a personal level (Akanin being literally a personification of the uncontrollable aspects of Mônica’s personality, meaning he highlighted many of her character flaws, and Amon being a thread to Korra’s ability to Bend, which is where she had placed all of her self-worth as being the Avatar, meaning Amon highlighted Korra’s insecurities).
• Go on a journey across four distinct fantasy realms (Mônica traveling through the Four Magical Dimensions, Laveidem being the medieval fantasy dimension, Tobor being the sci-fi futuristic dimension, Tchalu being the Asian martial arts dimension, and Edom being horror haunted house dimension. Korra traveled across the Four Nations, the Water Tribes being based on Arctic Inuit culture, the Earth Kingdom being based on Imperial China, the Fire Nation being based on Imperial Japan, and the Air Nomads being based on Tibetan Buddhist monks).
• Each of said realms grants them a different power set (Mônica’s species and equipment adapting to whatever Dimension she happens to be in, granting her the power set that represents said dimension, and Korra learning the Four Bending Styles from the Four Nations that allows her to control the Four Elements).
• Have a super power-up form (Mônica with ID Red, and Korra with the Avatar State) which are achieved by fusing with a spiritual being (Akanin and Raava) that represents another facet of themselves (Akanin being Mônica’s ID Monster that represents the uncontrollable aspects of her personality, and Raava being the Spirit that reincarnates alongside the Avatar through the cycle).
• Are accompanied in this journey by a group of their three best friends (Mônica’s Gang, and Team Avatar).
• One of the members of said team is a girl known for being highly clever and mature compared to the rest of the group (Maggie being shown to be the most mature of the group who often serves as the voice of reason, being the only one why didn’t need to fight her ID Monster, being able to just put her unnamed Monster into the ID Card immediately because it turns out she had already controlled all of the raw aspects of her personality before the battle against the ID Monsters even began, and Asami being the most independent and mature member of the team, as well as being a skilled businesswoman and industrialist), who also share a special relationship with the team leader (Maggie is Mônica’s best friend, and Asami is Korra’s girlfriend).
• One member of said team is a young teenage boy who is very easy-going and often used for comedic relief to break tension (Smudge being overall a very simple and friendly guy, and Bolin being an energetic and friendly person overall) who are linked to the element of earth (Smudge’s ID Monster, Kainin, being an Earth Monster, and Bolin being an Earthbender), and who have a close relationship with another member of the team (Smudge being Jimmy’s best friend, and Bolin being Mako’s brother).
• One member of said team is a young teenage boy who appears to be stoic and level-headed at first, but turns out to be a total goofball when you get to know them (Jimmy at first appearing to be a confident badass, which he is, but turns out he can be quite silly when the situation calls for it, and Mako appearing to be a super calm and serious guy, which he is, but he can also be a cute and kind person when needed), who also have a heroic side to them (Jimmy pretty much being as much of a shonen protagonist as Mônica, willing to leap into danger without thinking twice to save others, and Mako being highly protective of his younger brother and willing to put himself at risk to protect others).
• This aforementioned member (Jimmy and Mako) has romantic tension with the team leader (Mônica and Jimmy have a will-they-won’t-they style relationship, and Korra and Mako having a relationship where they get together but then break up later), which later on turns into an awkward love triangle thing (Mônica also having chemistry with Nick Nope of all people, who was considered the weird kid in the neighborhood due to him always being the contrarian, and Korra later getting together with Asami of all people, who was Mako’s other ex-girlfriend).
• Linked with fire (Mônica’s ID Monster, Akanin, is a Fire Monster, and Korra seems to use Fire as her go-to Element to attack).
• Often face off against threads, be them be from ancient times who are released after a long imprisonment (Zaheer and Vaatu), from modern times who use giant sci-fi vehicles (Black Hair and Kuvira), from their own world (Captain Frey and Unalaq), or from a world beyond their (Akanin and Vaatu).
• Steampunk setting (Mônica has had to play detective in a Steampunk world, and Korra lives in Republic City which is a Steampunk version of 1920s New York).
• Stories seem to lead to the literal end of the world (Mônica’s Adventure leading to the End of the World Supersaga, but we’re not sure how it will end because the Supersaga is not finished yet, and Avatar: Seven Havens taking place in a world devastated by a world shattering event that happened in Korra’s future, but we’re not sure what that is because Sevan Havens is not out yet).
• Series have references to iconic Japanese art (Mônica’s Adventures having a whole arc crossing over with the works of Osamu Tezuka, and the Spirit World in Legend of Korra being re-designed to look more like a Studio Ghibli film), and have also crossed over with iconic American characters (Mônica’s Adventures having a crossover arc with the Justice League, and Korra is playable in multiple crossover games where she can fight SpongeBob and other Nickelodeon characters).
• Rival networks (the Mônica’s Adventures cartoon airs on Cartoon Network, and Legend of Korra airs on Nickelodeon).

R1: Games + IDW canon surge Vs GT super 17

R2: full composite for both

Connections: They both did one Outerversal feat that involved going to the real world

Discord (MLP) vs. GOLB (Adventure Time) vs. Bill Cipher (Gravity Falls) vs. Alien X (Ben 10) vs. Black Hat (Villainous) vs. Invictus (Final Space)

Don't really know what else to put, I may or may not do art for a few of them, depends on how lazy I am.

These are the match ups;

"Imagining Fiends"- Mac & Bloo vs Vendetta (Foster's Home for Imaginary Friends vs Making Fiends)

"Towering Greed"- Peppino vs Wario (Pizza Tower vs Super Mario/Wario Land)

"A (ir)Regular Game"- Mordecai & Rigby vs 2011x/Sonic. EXE (Regular Show vs Creepypastas)

"The Masters of The Show"- Caine vs Master & Crazy Hand (The Amazing Digital Circus vs Super Smash Bros.)

"Calculated Cruelty"- Baldi vs Four (Baldi's Basics vs Battle For Dream Island)

"Mirror Match"- Fake Metal Sonic vs Metal Mario (Sonic The Hedgehog vs Super Mario/Super Smash Bros.)

"Faker's Paradise"- Kasane Teto vs The Doise (UTAU vs Pizza Tower)

"Brains of Doom"- Jimmy, Carl, and Sheen vs Zim (Jimmy Neutron vs Invader Zim)

"Papercut"- Paper Mario vs Miss Circle, Miss Thavel, and Miss Bloomie (Paper Mario vs Fundamental Paper Education)

This is Sam Wilson Best Match up so far

connections: both trios are popular to the internet community, they both have a mad genius (or just genius) with a soft side, a lovable member, and a chaotic member, 5 out of 6 of these characters work/worked for an evil, eldritch monster (Cyn and Black Hat), both have their own unique ships with a similar design, both teams have beaten multiple threats (Doll, J, Alice, J again, and Cyn, Mascara Macabre, Sunblast, Ms Heed, Bulldozer, and Black Hot). any other connections are ones i can't think of right now.

Flowery (DELTARUNE) vs Taiyo Asano (Yozakura Family)

Tried to do something different with this one. Hopefully it looks alright.