Otos are Loricarids, but I don't think they're really considered plecos.
There are a few species of pleco that look similar to the gold nugget. L018/L085 is supposed to get to 14" but I have never seen one that large in captivity. They're basically limnovores so they subsist mostly on the biological film that covers driftwood and tank walls. I've had one for about 2 years thats grown maybe an inch in that time, from 4" to 5". I've tried a few different diets and tank setups and nothing seems to have affected it.
I have seen a few different specimens of L014, which is called the sunshine or goldy pleco, up around a foot or so. It sounds like they're much better about taking prepared foods and thus are easier to grow larger.
For something relatively easy to find, a great smaller pleco is a bristlenose.
