Yes, a few Otos would be great to clean your tank

Or, one Siamese Flying Fox (if it's the
true one), or one Bristlenose Catfish. Two angelfish would work well too in a 29 gallon tank. If you get them, make sure there will be no other fish with "big personalities", as angels can get quite dominant. Also, be careful with adding tiny fish to a tank with angels - they could eat the small fish. However, my angelfish grew up with neons ever since they were very young. They never attacked or made any attempts at eating my neons. But it's very possible though, that when angels grow up only with other larger fish, and then they're put in a tank with small fish, they may very well eat the smaller fish. Plus, there are many other fish that are nice to have in a 29 gallon tank, either with or without angels. You could have 2 dwarf gouramis, for example, in a tank
without angels. Really, there are many possibilities. Maybe you should tell us first which fish you
personally like best and would like to have?