Wordbuilder O S T G H

How many words of three or more letters, including plurals, can you make only once? No foreign words or words beginning with a capital are allowed.

Good 7 Very Good 10 Excellent 13

Previous solution: ers, ops, ore, ores, ors, per, peso, pore, pores, pos, pose, poser, pro, pros, prose, repo, repos, rep, reps, res, roe, roes, rope, ropes, rose, sop, sore, spore