Are you quarantining any of these before you put them in the main tank? I can't help but think you're going to put something dangerous in there and wipe it all out.
I did that back in the 90's. At my peak I had 50 different kinds of plecos. Turns out, I like the more common(big) ones such as Rhino, Albino Sailfin, Normal Sailfin, Pardalis, Multiradiatus. Which yes are all in the Pterygoplichthys family