Hey Welcome. For suggestions on how to stock a 13g when your ready I have a few ideas. One way is to go with pairs of livebearers (guppies, platies, mollies, swords) to a max of about 10. Another way is to go the tetra kind of root (neons, cardinals, serpae, pristella, rummynose), in two groups of five, or just one group of five with two "slightly" larger fish (dwarf gouramis, rams, dwarf cichlids). There are plenty of ways to go the best way I find is to take a look around and find the one "must have" fish and build your tank around the goal of having this fish (keeping in mind it's maximum size), find appropriate tank mates to go with you "must haves", maybe add a couple small bottom feeders or algae eaters (corys, otto cats, clown or bushy nose pleco). So I hope that starts you thinking. Do you research and if you have more questions just ask.
