perhaps add a last highlight to the blades for a crisp, bold look. It will add more character and depth to your tiles

Well I felt your last grass was pretty but it needed more drama (for grass blades) if it wants to measure up to the holy Seiken Densetsu 3 grass tiling--those people who made it are just amazing. I am amazed that they KNEW they could make stuff GREAT and they did it, they didn't give up they made it.

So I took your X grass, took out the dark green background, then I added some highlights to the grass blades and pasted them over the new grass. I came up with this:
Here's the original tile:

Perhaps a little dirty looking, but I feel it portrays grass a little cleaner. I'd also try to more monochrome the colors/reduce the contrast if your characters are meant to stand out particularly well on the tiles. Right now the tiles have some character

This is amazing! You should make a game with me!

Your grass is fine! Add more blades, add more shading. Then repost it and we'll see if anything else needs done