Pitbull Pleco is a tiny tiny thing but I can't seem to find them for sale anywhere
Bristlenose plecos are good for removing algae and do not become large like common plecos. If you're looking for a small pleco that doesn't work too hard clearing algae, then the clown pleco may be right for you.
If you would consider a species that is a catfish, but not a pleco, Otocinclus does a nice job.