I’ve been playing with papercraft stuff, as it’s a little easier for me. I don’t have a good workspace for painting, but I can get away with scissors and craft knives at the dining room table. I don’t have the skill currently to create enough interesting texture and depth using paints, so printing stuff from actual artists gives me better output.
For fantasy / dungeon stuff, I’ve just started trying out Crooked Staff models, following his simple 2.5d build instructions.
For sci-fi, I printed off these platforms, and also these Sci Fi tiles (again from Crooked Staff). I’m currently working on building a floorplan from these for some upcoming Flight of the Red Sword sessions. (Photos to come soon, I hope!)
There’s also a huge assortment of really great, free models at Genet Models. The Module::Core, Derelict II Megaset, and Firebase Maginot all look great.