Azumanga Daioh, Megaman, Full Metal Alchemist, Virtual Boy, Jigsaw(I think).
Some I recognize, but can't put a name to.

>>2274
Beyond those I see Yotsuba&! and maybe JoJo (the stone mask, perhaps which the other anon thought as Jigsaw?)

At a quick glance (in addition to >>2275) Toriyama Akira, JoJo, Cardcaptor Sakura, Detroit Metal City, Danbo/Yotsuba&.

>>2274
Other than those already said, Raising Heart from Nanoha, Zero's helmet from Code Geass and Bonta-kun from Fullmetal Panic. Also I think that little lump down there is the Clannad dango.
The armor in the back looks familiar but I can't quite place it.

Adding to >>2278, top left is that character from Moyashimon, far right is Satchii from Dennou Coil

>>2274
I doubt it. I tried looking up the answer afterwards in both Japanese and English, and while I could find various attempts, surprisingly I couldn't find a definitive list anywhere.

Multiple guesses have been made before that the bottom one is the Clannad dango, but the eyes don't match. They look like Pac-Man's eyes, but then the figure lacks Pac-Man's eyebrows. So I don't think either of those are right, unless the design was intentionally modified to be legally distinct or something.

>>2279
I thought it was Haro from Gundam. Not like the eyes match either, but it's green and roundy.
For some reason there's videogame references too, I can't at least notice the Virtual Boy and Seaman.