Printable Scenery has some solid stuff.
Paid, but some nice options.
I like their overall theme, but for
40k it just seems its either gothic structures or bust.
I am on the lookout for non gothic ruins, more industrial. OR barricades and such.
Thingiverse is always a good place to check out, also you could try searching for CC0 3D Terrain/scenery etc, it should throw up a lot of public domain items that you could download and print for free
I do like thingiverse. I am in the hunt for more detailed 3d print files!
Automatically Appended Next Post: Found a interesting one called:
myminifactory.com
https://www.myminifactory.com/object/3d-print-warhammer-30k-40k-compatible-terrain-outpost-basic-version-51768
pretty cool set up there. will be combing thru this.