& Knuckles.

and Dante from Devil May Cry

and Sephiroth

and a goomba (srsly why is he not playable in Mario spinoffs already)

Super mario party tho

oh right

Here is a list of characters I think deserve a spot in by category of why they would be good to put in. These are only characters that I feel deserve a spot more than any others in their respective category of why.

Great characters that are in the main smash series:

Ryu: Being an iconic fighting game character as well as playable in smash 4.
Mewtwo: One of the most interesting movesets and movement of any character in smash.
Little Mac: He has the KO bar, which is a custom mechanic that would make things intersting.
Shulk: The ability to change a characters stats in different situations would be freeing.
Greninja: Very smooth movement, and a unique and devistating (if mastered) moveset.
Cloud: Need I say more?
Bowser Jr.: A very different character that had some pretty good moves.
Rosalina: The ability to use Luma made playing as her very fun.
Ganondorf: I don't think this needs explaining either.
Lucas: Ness needs his partner back.
Fire Emblem characters: All of these characters are just different enough for them to deserve a spot.
Snake: I feel as though we need those guns and explosions, as well as the diversity of a MGS character.

Popular characters that other fan games offer:

Ridley: Very unique and heavy with a large hitbox and slow but powerful moves.
Shadow: Huge potential for a very unique and fun moveset and a must in the sonic universe.
Scorpion: The most iconic fighter from the legendary Mortal Kombat franchise.
Tabuu: The boss from Brawl. I know this seems strange, but it's kinda the same concept as ridley, but faster and harder to control.
Skull Kid: A vintage enemy from the zelda series that could have a flexible and effective moveset.
Banjo Kazooie: This was a huge character back in the day and it would be very neat to see him join in.
Crash Bandicoot: A huge mascot of the Playstation and still a well known character today.

Characters that were in the first smash flash:

All fan characters: One thing I enjoyed was having exclusive characters.
Mr. Incredible: Almost a humorous addition to the roster, this character kind of stepped outside of the box and had cool moves.
Shadow/Cloud/Mewtwo: I know these are in the previous lists, but I felt like they needed another honorable mention.
Knuckles: This would top things off in the sonic universe with our beloved tough guy, having the ability to glide.
X: I recommend Mega-Man X not just because it was in the first, but to suggest a move for him or mega man that changes their attack attributes while having the other use a variety of moves in one form.
Zero: This character is arguably the coolest character in the Mega-Man universe and had great moves.
Inuyasha: An iconic anime character from an age where anime was just getting really big in the US and a nostalgic touch.

Characters that I think deserve a spot in the final version (arranged by universe):

Mario:
-Boo: I think this would definitely make an interesting character.

Zelda:
-Goron Link (Darmani): This could be a heavy character with strong punches and the rollout like move as it's down special.
-Zora Link (Mikau): It would be awesome to see those boomerang fins and energy barrier used in smash.
-Deku Link: This character would have some weird controls and I wouldn't say it's as important as the goron or zora, but it would be cool.

Naruto:
-Sasuke: Of course I would suggest this. He is the second most beloved character.
-Itachi: A great character in the universe, and technically a villain in the series.
-Pain: Arguably the most iconic bad guy in Shippuden (and my personal favorite).
-Madaara: The most powerful Villain in the series.\
-Kakashi: Definitely one of the most beloved characters, and one that we all met early on in the series.

Dragon Ball:
-Vegita: Being Goku's counterpart, this just seems natural.
-Frieza: The first villain we meet, and most people's favorite.
-Majin Buu: Strongest antagonist in the series as well as being a regular ally in Super and having very good potential for nice moves.
-Beerus: The god of destruction and one of our strongest friends.

Sonic:
-Silver: I think his psychic powers would make him more interesting as a character than as an assist.
-Gamma/Omega: Having another robot in the game would be nice, and why not let it be one from Sonic?

Mortal Kombat:
Sub-Zera: Of course, one of the most iconic characters in the series.
Liu Kang: The main character with very memorable moves that would grant fans excitement and nostalgia.
Shao Khan: The main antagonist in a few games and a large character that would change things up a bit.

SoulCalibur:
-Nightmare: One of the most popular characters and the wielder of soul edge.
-Ivy: Probably the most iconic character of the series.
-Kilik: Now the edge master, and could have a special move that gives him a random weapon.
-Maxi: This is a favorite of a lot of fans of SC and it would be our first character to wield nunchucks.

Marvel:
-Spider-Man: A beloved super hero that anyone would love to play as.
-Venom: A favorite super villain in the Marvel universe for lots of fans.
-Deadpool: Another character with guns! Couple that with swords, martial arts, and acrobatics and we have a diverse character.
-Wolverine: Everybody's favorite X-Man!
-Iron Man: The jet boots, the plasma blasts, cool armor, super strength, and witty sarcasm. Who doesn't love Iron Man?
-Thor: The god of thunder and easily one of the most powerful heroes in the franchise.

Star Wars:
-Darth Vader: I know this seems corny, but I feel as the pinnacle of fan made smash games that SSF2 should have Star Wars characters.
-Luke Skywalker: One of the strongest force users who ever lived (if not the strongest) and beloved protagonist of the original trilogy.
-Starkiller: The star of the Force Unleashed games and easily one of the strongest force users we have ever met.
-Yoda: The wisest and eldest Jedi Master. A true master of the force and the teacher of many Jedi including Luke.

Yu-Gi-Oh (I know I might get laughed at for this and no one will probably care, but I feel this could have a place):
-Dark Magician: One of the early mascots of the franchise and has potential for interesting moves.
-Flame Wingman: The mascot of GX and a very interesting character.

Fairy Tale (If we are doing anime I think this deserves a spot):
-Natsu: Main character of the series and one of the strongest.

Turok (You may not know what this is but if a dev who happens to be a Turok fan sees this, please push for this!):
-Tal'set: Native American hunter man who could add some diversity to the game, especially with some guns!
-Joshua Fireseed: Main character in the 2nd and 3rd games. Had a great arsenal of weapons.

Skyrim:
-Dragonborn: Please... this would be epic...

Bowsette

King Boo.

Mario's arch-enemy is in the game, so why not Luigi's own arch-enemy.

And we need more "kings".

No brawl modder has ever attempted Pegasus Seiya, and I've only ever seen incomplete versions of Jotaro Kujo and Klonoa.

Crusade made a good Klonoa though.

Cue the Jotaro mods once the game enables Expansion Fighters.

Shy Guy.

Captain Toad.

slippy toad

an actual toad

A lemon