Mollies
cardinal tetra
neon tetra
black neon tetra
danio erythromicron
galaxy rasbora/ celestial pearl danio
rummynose tetras
sterba cory cat
zebra danio
Tank pH would be a good start........???
So My thought is that you are right to think you don't want too many groups of tiny fish.
I had 2 groups of 12 or more of Glowlight and Cardinals which are beautiful fish types and I love both (Cardinals better though) because I also had a group of about 15 Harliquin Rasbora with then and they are similar color to the Glow lights...too much little fish.
It would have been better with one color group say the Cardinals of 20 then the Harlequins.
The Celestial Pearl Danios are one of my new favorite fish! But they are tiny and I think since their pattern is so lovely, they should be in a tank which is seen very close up to really enjoy them and for that reason I would not put them in there (55G). They do school well and stay together even though they may split into 2 groups of 5-6 (I have 12).
So lets say one group of slender body fish like Cardinals, and a group of larger body fish like the Harlequin Rasbora or Diamond Tetra.
And some larger fish, I had a group of 6 Millenium Red Rainbows and I absolutely loved them. Or other group of larger sized Rainbows, just decide on one type because they will cross breed. One male for at least 2 female or 3 or 4 lol.