Don't get anything that is a fin-nipper (puffers, triggers, etc) or less than about 3" or 4" depending on body shape (cigar-shaped, long/thin fish...think of slurping "spaghetti"). It's hard to pick fish for other folks as we all have different tastes. The other thing is you need to shop for fish according to your "loss tolerance"...how upset will you be if something gets eaten or doesn't work out, and always have a "Plan B" if something goes south.
We keep a trio of
Odontanthias borbonius (blotched anthias), and have kept bristletail filefish with our small lions and scorps, but I know unless you find an awesome deal (we did), the anthias can run a couple hundred each. Anthias are pretty colorful fish, and many would be fine with a dwarf lion, but you need to be sure if you want to get "multiples", that you get a species that won't kill each other off.
The "blotchies" are pretty great-looking fish tho...