Corys and betas get along famously. If you have a soft sandy bottom, or an other wise unjagged substrate. [if it is sharp it can cut their wiskers & they'll die because they won't be able to find their food.]
Harlequin rasboras are great too. Amano Shrimp, Cherry Barbs (two females/male), Neons or Cardinals, rummy nose rasboras, Plecoes_ All happy cohabitators.
I'm not certain about angels_ I've definitely done it before without stopping to think about it and didn't have any problems, but I may have just been lucky. It was a long time ago.