I kind of wish patterns were standardized because some levels use a specific pattern for grass, wood or stone and then another uses different patterns for those 3. And then there are folks who just started out and they use the default checkerboard pattern because they don't know how to change it.

Here's my personal takeaway:
-Anything that is not flat, like it's jagged, uses the triangles. (for example grass)
-Anything that is soft uses circles. (for example dirt)
-Anything that is solid uses squares. (for example stone)
-Anything that is smooth either uses nothing (pattern w opacity 0) or diagonal lines. (for example roads)

These are consistent across all my games, even the ones that aren't out yet.

Additionally:
-I used wave patterns for fallen tree wood, snow and sand (although I also used triangles for snow because I'd assume grass would poke out of it)
-I used crosshatch patterns for cloth (like the tent in one of my games) or hay. Also had to use it for a palmtree i turned into a small flower because coloring the wood to look like a stem while keeping the "capitulum" yellow was impossible.
-I used the hexagon pattern on a futuristic building. I can also see it being used on a turtle shell, but this one is pretty hard to find a use for.
-I used the spiral thingy on gravestones, bt it's probably usable for other builds too.

Personally ive always seen grass to use the checkerboard pattern solely cause thats how all grass has looked in bopimo since the dawn of No Thumbnails but thats just my opinion probably

for grass i use waves for bricks i use bricks and i use checkerboard for stuff that doesnt have the pattern i want like smooth we need that