Various sources as it's the standard in ALPS and Okachimentaiko doujinshis.
01 Mai Shiranui, from Fatal Fury. 03 Multi, from To Heart 04 Akari Kamigishi, from To Heart 05-13 Rain Mikamura, from G Gundam 14-21 ??? 22 Casca, from Berserk 23-30 Kasumi and Satoshi, from Pokemon 31 ? 32 Yurika Misumaru, from Martian Successor Nadesico 33-37 ? 38 a girl from Sakura Wars whose name I don't remember 39-54 girls from Mamotte Shugogetten 55-60 girls from Soul Calibur (I would never recognize, but the name of the series is there) 61-72 Mai Machiko, from Miss Machiko (Maicching Machiko-sensei) 73-81 ?? 82 Ayanami Rei, from Evangelion 83 Asuka Langley, from Evangelion 84 Ritsuko, from Evangelion 85 Musashi, from Pokemon 90 Aoi Matsubara, from To Heart 92 someone from Rival Schools
13 is the princess from St. Seiya. 14-17 MIGHT be Kasumi, Tina Armstrong, and Ayane from Dead or Alive?
18-20 are Gundam girls: 18 is Cima Garahau and 19 is Nina Purpleton. Not sure who 20 is - maybe Cima with inverted hair? - but she's wearing a Zeon jacket.
I think 31 might be Lisa Hayes from Robotech/Misa Hayase from Macross, because I feel like 72 is Minmei from the same show.
33 is the lead girl from GaoGaiGar. I think 33-36 are aged-up versions of the girls from Cardcaptor Sakura (a winged lion was her familiar); maybe 37 is her mom or another character from the series?
Going by the body-shapes, 55-60 is early work by the artist who now goes by Matsurino Naginata.
72-73: Elena from Street Fighter. 75-76 are Vice, Mature, and Shermie from King of the Fighters. 79 and 80 are Tifa and Aeri(s/th) from Final Fantasy 7. The Rival Schools girl on 92 is Tiffany Lords.