The textures used for the tops and sides of grass blocks, mycelium, podzol, grass paths and nylium do not seem to be named consistently. It may be desirable to rename some of these files to alleviate confusion for resource pack makers, among other things.

Grass block: grass_block_side.png, grass_block_top.png
Mycelium: mycelium_side.png, mycelium_top.png
Podzol: podzol_side.png, podzol_top.png
Dirt Path: dirt_path_side.png, dirt_path_top.png
Crimson Nylium: crimson_nylium_side.png, crimson_nylium.png
Warped Nylium: warped_nylium_side.png, warped_nylium.png