A thing I like to say, it's not how often a tileset is used, but how you use it. Desolation is commonly used, but its versatility allows to create a lot of unique looking levels.

Of course, there are plenty of commonly used tilesets with levels that look the same, due to the creator not caring about how it'll stand out. Or the tileset has already been taken to its limits. Many test levelmakers don't give a shit about the eyecandy, so that's why 95% of top secret levels end up looking the same.

I think top secret doesn't look too bad, but it's nothing really impressive either. It's used a lot, because it's the least ugly tileset that's good for tests. I admit the 8x8 background sucks though. Ugly colour loss and doesn't work properly as textured. I consider that School V3 looks worse than top secret.

Not all tilesets are commonly used for the same reason. It comes down to ease of use, what it offers for the level and (ofc) how it looks. Mystic isles is fairly popular due to ease of use, yet looks mediocre.

Some decent looking tilesets are rarely used, due to being far too limited. Please, whenever you make a tileset, consider user friendliness, what else that could be done with it, the backgrounds, and what events fit with the theme. Slimeset may look decent but it's seriously lacking in a lot of things. You'd be taking to it to its limits the moment you use it adequately.

Also, what is krype? Typo much? Something you found in your cache? Because searching gives no results whatsoever.
EDIT: Nvm, SE sent me it. Reminds me of my first tileset that was cancelled, due to how much I improved since then and lack of inspiration.

Being evil aside, I've wanted to remake a couple of tilesets with good themes (rare and fairly commonly used), but redrawing everything from scratch. I called it the Realms Remastered project. It's something I had in mind for a long time, but the way I draw tiles is cumbersome. They usually look good (and much better than the original), but hard to tile.

I don't know if I'd participate in this. If I did, it would involve remaking a tileset or working more on my current remakes. And I'm really unreliable. Sure, I wouldn't need to completely finish it, but I need a minimum.