Get relatively peaceful dwarf cichlids!
I'm super happy with my tank atm with 4 german blue rams (2m/2f which appear to be pairing up into two separate pairs) a fully grown pearl gourami for that one larger fish aspect, some cories at the bottom, oto's and then a school of tetras. I've got 12 penguin tetras but really any set of preferably mid-upper water level swimming tetras would work
The blue rams are little jewels and so much fun to watch interact, if you don't want to keep your tank at 78+ and want slightly hardier fish bolivian rams would do just fine instead.
However I'd wait with the rams until your tank has been stable for a while they can be pretty sensitive. Good news is though that just with the rest of the fish (pearl gourami and tetras and cories) the tank will still be fun to look at.
..and yeah it doesn't have to be a pearl gourami, but it's one of my favourite fish, gorgeous under lights and gets relatively big while staying fairly peaceful. Def the most peaceful of the gouramis I think, what then the slightly bigger ones.
ETA: For cories I'd get either sterbai cories or adolfoi, leaning towards the adolfoi
