Wow, Wikipedia is pretty minimal in giving examples. Clicking through various links in comments for more examples should be considered mandatory (though many of the 3D ones are actually "some effect on top of Truchet").

I suppose I don't normally think about how you're actually using minimal Truchet tiles when you play one of SGT's puzzle games, since it's the most boring tileset:

https://www.chiark.greenend.org.uk/~sgtatham/puzzles/js/slan...