Nice-looking products. 3D printing must be great for small businesses like this!
Add my vote to printing outdoor stuff. Trees, vine-covered altars, stone and wood walls, swampy stone slabs, tents, campfires. Things that can go on a printed base map (something like Heroic Maps) to add interest. Things like the Dungeon Magic Circle.
Also consider standing stones. Many years ago I ran a game vaguely themed around sentient standing stones and I couldn't find figures for them. I tried making them, but I'm not very good. If you offered something that would let me recreate Avebury or Stonehenge, I'd probably buy them, painted or unpainted.
Except that I won't be buying them, because you don't ship outside the USA.
However, I think your products share an issue with the Dwarven Forge products, namely the height of the walls.
I play in a game where one player has spent many, many hundreds of dollars on Dwarven Forge items, so he likes to show them off. He builds huge elaborate dungeons. However, once the walls go up and the figures go in, I can't tell what is going on without standing up, leaning over and looking directly down. From a sitting position, I can't see anything past the walls.
Have you considered making half-height walls? Maybe 10-15 mm? Something that indicates "here is a wall" but that doesn't block players' vision?
Anyway, good luck with the business.