Super Smash Buddy

Super Smash Buddy would be just super smash bros except its 2 player and always tag team

Characters
Mario/Luigi (Super Mario)

Kirby/Yoshi (Kirby's Adventure and Yoshi's island)

R.O.B/Samus (Giromite and Metroid)

Scorpion/Link (Mortal Kombat and the Legend of Zelda)

Ness/Lucies (Earth Bound)

Fox/Tails (Star Fox and Sonic the Hedgehog)

Donkey Kong/Banjo (Donkey Kong Country and Banjo Kazooy)

Unlockable Characters
Pikachu/Raiden (Pokemon and Mortal Kombat)

Jiggle Puff/King Dedede (Pokemon and Kirby)

Captain Falcon/Falco (F-Zero and Star Fox)

Snake/Sheik (I know Zelda is Sheik) (Metal Gear Solid and Metroid)

Heiachi/Ryu (Tekken and Street Fighter)

Duck Hunt Dog/Shang Tsung (Duck Hunt and Mortal Kombat)

Ike/Meta Knight (Fire  Emblen and Kirby)

Sonic/Mega Man (Sonic The HegdeHog and MegaMan)

Bowser/Ganondorf (Super Mario and the Legned of Zelda)

Mewtwo/Lucario (Pokemon)

Dr.Mario/Wario (Dr.Mario and Wario Ware)

Crash/Spyro (Crash Bandicoot and Spyro the dragon)

Bosses (Unlockable by cheats)
Master Hand/Tabuu (Super Smash Bros)

Giga Bowser/Orger (Super Smash Bros and Tekken)

Dr.Wily/Dr.Eggman (MegaMan and Sonic the Hedgehog)

Eyedol/Shao Kahn (Killer Instinct and Mortal Kombat)

Maxwell (Scribblenauts)

Modes
Regular fight: When to couples fights (eg. Mewtwo and Lucario vs Ike and Meta Knight)

Buddy Brawl: when the two buddies are fighting (eg. Mewtwo vs Lucario)

Arcade Mode: Just like all arcade modes but at the you fight the bosses

Story mode: you know