This is a roughly organized list of all characters with custom variant suits that can be created, the base mobile suit is placed next to the characters name. All names are of their English variant.
Mobile Suits
Solomon: Zaku IIF, Zaku R1, Gyan Type B. Gelgoog High Mobility Type, Zaku R
Tem Ray: Gundam
Dido Kaltoha:RMS-119 EWAC Zack "Eye-Zack", Desert Zaku, A Type Gelgoog
Elo Melloe: RMS-119 EWAC Zack "Eye-Zack", Desert Zaku, A Type Gelgoog
Ma Queve: Gouf
Gyunei Guss: MSN-03 Jagd Doga
Nimbus Schterzen: MS-08TX Efreet
Johnny Reiden: Gyan Type B, Gelgoog High Mobility Type, Zaku IIF, Zaku II R
Char: YMS-15 Gyan, Gelgoog S Commander Type, Z’Gok S, Zaku II C, Zaku II S, Rick Dom
Quattro: Rick Diaz
Anavel Gato: YMS-15 Gyan, Gelgoog S Commander Type
Ramba Ral: YMS-15 Gyan, Zaku I, Dom, Gelgoog S Type
Black Tri Stars: Zaku I, Gelgoog High Mobility Type, Dom, Zaku R1 A, Gyan Type B
Rezin Schnyder: Giradoga S Commander Type,
Puru: Quebley
Puru II: Quebley
Cima: Gelgoog Marine, Gyan Marine S
Garma Zabi: Dop, Zaku II S
Dozel Zabi: Zaku II S
Amuro: Z + A1
Haman: Gaza C