I am probably missing somebody and replacing them with somebody else, but from first thought:
1 AM2 -- VF series, Daytona, Shenmue, Outrun, Space Harrier, Hang On
2 Capcom -- SF II and SF Alpha
3 Atari arcade division of the 80's -- Ed Logg et al. for Missile Command, Centipede, Battlezone, Asteroids
4 Williams / Kid Vidz team -- Eugene Jarvis, John Newcomer, et al. for Defender, Robotron, Joust
5 Namco -- Soul Calibur, Ridge Racers, even Pac-man World 1&2 and older stuff like Xevious, Pac-Man, Tower of Druga, Pole Position II
6 Sonic Team -- Sonic the Hedgehog series, NiGHTS, Burning Rangers, Chu Chu Rocket
7 Treasure -- Dynamite Headdy, Gunstar Heroes, Guardian Heroes, Radiant Silvergun, Ikaruga
8 AM3 -- Sega Rally ( I think it was AM3)
9 Lobotomy -- RIP but they were impressive in their day -- see Powerslave Saturn!
10 Delphine -- Flashback
