Pyramid Head (Silent Hill 2)
Ganon (The Legend of Zelda: Ocarina of Time)
Flaahgra (Metroid Prime)
Bitores Mendez (Resident Evil 4)
The Hive Mind (Dead Space)
Leonard (Silent Hill 3)
Neff (Altered Beast)
Metal Sonic (Sonic 3 & Knuckles)
Mary (Silent Hill 2)
Dr. Zomboss (Plants vs. Zombies)
Scarlet (Silent Hill: Homecoming)
Bowser (New Super Mario Bros.)
Mother Brain (Super Metroid)
Cut Man (Mega Man: Powered Up)
Medusa (Castlevania: Lament of Innocence)
Metroid Prime (Metroid Prime)
Del Lago (Resident Evil 4)
Dark Samus (Metroid Prime 2)
The One Truth (Silent Hill 4: The Room)
Wart (Super Mario Bros. 2)
Silver (Sonic the Hedgehog)
Crocodile (Resident Evil 2)
Uroboros (Resident Evil 5)

I'll Stop there cuz the BOSS List could go on & on ;)