Yeah, I have a general stocking list for peaceful South Americans that scales up with the tank size. For a 6’ tank, my pattern is (including my real life stock list in my 180):
1 large cichlid/pair of larger cichlids as centerpiece (uaru)
6 medium cichlids, typically social species (geo Tapajós red head)
2 borderline dwarf cichlids (burjuquina vittatus, yellow throat acara)
1/1 pair of dwarf cichlid (ivanacara adoketa, single male who is a bully)
1 or 2 schools of tetra (lemon tetras)
Group of peaceful catfish (hoplo cats, can’t recommend these guys enough)
1-2 plecos (Royal pleco).
For a 75, I would scale it down (examples for species in Parentheses):
One medium pair of centerpiece cichlids (krobia xinguensis, aequidens pulcher either reg or electric blue, cleithracara maroni, biotodoma cupido, etc)
6 smaller social cichlids (guianacara would be good IMO)
1 school of tetras (penguin, panda, lemon, emperor, kerri, rummynose, etc)
2-3 catfish or school of cories (hoplo cats are always a good choice, porthole cats would work as well)
1 pleco (avoid the larger guys, nothing over 8” IMO)
That stock list will provide variation, and as long as you are decent at water changes will be just fine. Hopefully that helps a bit.