Got 'em:
The Makon one actually has Mario 3 Special and Sonic Adventure 7 on it, along with King of Fighters 96, Tarzan Lord of the Jungle and a bunch of older gameboy games. No repeats. Mario 3 Special and SA7 appear to be the only Gameboy Color games on any of the carts. Amusingly enough, the cartridge looks to be of GBC design from the front, but posesses the side-notch so all of the normal-GB games on it can be played on a black and white gameboy or GB pocket. When played on the Super GB they worked in a compatibility mode for original GB.
The game select screen reads "SUPER 23 IN 1 NEW SUPER MARIO 3".
The Gray one has no bootleg games and no pokemon pinball. It has Blaster Master Boy (one of the rarest/most valuable Game Boy releases in the US) and Pop Up (a UK exclusive) and Super Dodgeball (Japan) but nothing else of note. No repeats. This one seems the most sturdily built, though the Makon cart is close.
The game select screen reads "KT7006 07 IN 1". There is also a sticker on the back of the cart with "KT" and a bunch of number boxes on it.
The yellow ones both repeat. The 10-in-1 has 5 actual games, the 20-in-1 has 9 actual games. The only games of note on each are Battle Crusher (JP only mech battler) on the 10 in 1 and some Ultraman game on the 20 in 1. There's also a Dragonball tactical fighting game with a storyline on the 20 in 1, but it's not translated. The rest of the games on them are either uninteresting or incomprehensible.
The game select screens read "KING SERIES 10 IN 1" and "KING SERIES 20 IN 1".
Since the Makon one DOES have SA7 and especially Mario 3 Special, it's still a good buy but sadly offers nothing new to the scene.