Obviously anything you do is a personal preference. My next tank I would set up a Zebra Obliquidens or Pundamilia nyererei. There are a few Victorians that I would like to have a tank for.
I have this idea of a convict colony.
1m3f Honduran Red Points
1m3f Nanolutea
Big pack of bleeding heart tetras
1m9f Swordtails
1m1f Blue Fin Panaque
3 Flagtail Porthole catfish
Army of Nerite snails
You could do a lot with a 125. Dozens of threads about it too. You could do:
A pair CA/SA cichlids of your choice (Oscar, Jack Dempsey, Green Terror, etc.)
Oddball tank (smaller bichirs, leopard ctenopoma)
African cichlid route with some peacocks
A general community tank (a bunch of livebearers, gournami, tetra, etc)
Unless you plan on getting a larger tank stay away from arowana, peacock bass, and the RTC
There’s a bunch of other options just do some research