Actually, making all these tilesets is a very long job!!! I only show screens when I get enough tiles available.
For instance, for some tilesets (and I mainly think about the Pillar, Sci-Fi and Rock/Dirt tilesets, here), I'm on it for more than a year (of course, I don't work on them on a regular basis, but the fact is that I started working on these tilesets more than a year ago... and I'm still not fully satisfied with them).
Generally, I'm not pleased with my 1st drafts, and I discard many (all?) tiles from new tilesets. I work and re-work the tilesets a lot! (and speaking about that, I think the tileset on which I failed the most is "Rock/Dirt". What a nightmare to get this nice Lemmings' Dirt touch!!!... and, as today, I'm still searching for the "
magic"
I'll keep on working on it.)
I can say the Brick, Marble, and Colors tilesets are finished (except, atm, I still miss the Steel blocks and Objects for all tilesets). Other tilesets are subject to changes. And I can add that I would like to have a "Fire"-like tileset for the game. (still not sure I will add it, though)
So, to conclude:
it usually takes me quite a while to create each one!
... for me, too!