It's a mixed bag because it depends on what I've been exposed to in a given fandom and what mood I've been in while reading, but I've got a lot of recs in a lot of different fandoms.
All the CLAMP recs are listed together because I really, really didn't want to try to figure out which fandoms were which and which were truly separate from each other.
You might also try rec_a_day and tomomichi for some recs. I don't always agree with either of them, but I do often enough, and they do rec in some of the fandoms you listed and often rec shortish pieces.
The only drabbles coming immediately to my mind are daegaer's Weiss Kreuz drabbles. If you don't mind Weiss, her various drabble series (she tends to do very long series of connected drabbles, often writing out of order).
no subject
It's a mixed bag because it depends on what I've been exposed to in a given fandom and what mood I've been in while reading, but I've got a lot of recs in a lot of different fandoms.
All the CLAMP recs are listed together because I really, really didn't want to try to figure out which fandoms were which and which were truly separate from each other.
You might also try
The only drabbles coming immediately to my mind are