Pro Motion, GrafX2, Pyxel Edit all do this.

I'm not finding the exact tool I was looking for in any of those three programs. I might not have explained it well. I thought in the past that I had seen a program where you could edit a single tile in one window, and in another you could see a 3x3 gird of that one tile repeated 9 times so you could see how it would link up with itself if used it in a game.

Did I not look under the correct settings or am I thinking of a different program? I do see options for creating tile sets, I just don't see an option to show a grid of just the same tile as it would look pasted next to itself in a 3x3 grid.

They let you do stuff like this:
(by Arachne)

If you want to see a 3x3 grid, then just place that on the canvas.

Personally I'd like to see a display/edit toggle to fill the canvas with the currently edited tile, but none do that that I'm aware of.

There are no tutorials that I know of, or at least none that go into any real depth, but the in-program help is very comprehensive.

Edited by MrWallas - 15 June 2014 at 8:14am