These look like the first EZGBZ mountain set, but worse. For one thing, they're too even, giving away the tiling. EZGBZ's mountains are very obviously tiled, but while those were tiled in 16*16 pixel chunks, these appear to be tiled in 8x8 pixel chunks. This repetition makes them look much more man-made and that's not a good thing to have with mountains. I also don't like the two pixel wide lighting on the mountains. Most other EZGBZ mountain sets have one pixel wide lighting and the one that does have two pixel wide lighting alternates between one and two pixels to show texture. Here it just feels very flat and would be out of place with the rest of the set. One thing I do like are those top parts in the second set, they look much more mountain-like than the weird blue fence type things the originals have. I think if you keep trying, you'll get it right. Overworld tiles are tricky, I certainly couldn't do better.