
Top left one im unsure who the artist is, so starting from 2nd from top left:
Junko Yagami - Lonely Girl VG+/VG
Keiko Mizukoshi - Aquarius VG+/VG+
Hi-Fi Set - Love Collection Ex/VG+
Asami Kado - Fascination Ex/Ex
Circus 1 - Circus Ex/Ex
God Mars BGM Collection 4 VG+/VG+ (not disco but some nice moments on this one)
Tinna - 1999 Ex/Ex