Depends what you call small but to me something 5 inches and smaller is fairly small, prices vary
the black and white spotted ones in my pics are L201 snowball plecos, they get about 4 inches. There’s a dwarf variety L471.
some other smaller varieties are l134 lepaofrogs, l052 butterflies, l260 queen arabesque, l135 wormline, l183 stary night, l129 columbian zebra, l236, l46 zebra pleco, l239 blue panaque, l004 angelicus….be forewarned once you get one you’ll want them all haha