Can you help me stock my 20 gallon aquarium?

plz do not buy any angelfish or cichlid, they grow pretty big and i was advised to only have 2 in my 55gallon. My first tank was a 20g high and i had sort of a "ocean/beach" theme which i regret taking down. It had 5-6 neons, 2 glo-fish, some guppies which most died on me, and 1 black 4 inch catfish which i could never find it's name or where i got it from, cause i would love to have it again. If i were to have that 20g again, i would stock it up with 8 neons, a nice bottom feeder, and maybe 1 or 2 others you might like, as long as they are community and under 3-4 inches...