For day to day miniatures I prefer the original D&d minis. They’re hard wearing and there are some great minis in those sets. Pathfinder minis are a close second the sculpts are generally really good even if they don’t map exactly to D&d monsters. They can be brittle though. The D&D Whizz Kids models are generally pretty crappy. Bad sculpts, brittle and the scales whilst more accurate make the minis look quite underwhelmjng in cases. Pathfinder minis suffer the same but less so.
For PCs I think reaper are excellent. There’s something satisfying about metal minis for PCs and their catalogue is so huge you can usually find pretty much anything you are looking for.
For epic monsters you can’t beat games workshop. Their hydra, chimera, black dragon, cockatrice, jaberslythe, giants etc etc are simple beautiful. Though expensive they’re true display pieces when painted.
Speaking of epic, the Gale Force 9 miniatures are also beautiful, particularly the demon lords sets. I’ve shared this image a few times and particularly love Demogorgon and Orcus. That mini alone makes me want to play Rappan Athuk again!
Last but not least, I think the gold standard for scenery has to go to Tabletop world. I’m lucky enough to have a few pieces by them and they are a pleasure to paint.
All pictures are mine. Apologies for some dodgy paint jobs