I'm feeling like lots of blocks are still missing in Valley! Some examples below.
FOLDER 1-5

More blocks like these, also blocks like these for the lower mountains/cliffs.
FOLDER 2-5

More turn possibilities for the 4-2 block collection!
FOLDER 4-1

First, a platform start and finish block instead of just checkpoints and a multilap block. I'm talking about these (above) in folder 4-1. Also make the slope checkpoint blocks (4-1-8 and 4-1-9) go left and right instead of just up and down! And PLEASE!! Less pilars in the parking garage platform blocks!!
FOLDER 4-2

Give these the same blocks as the platform parking garage blocks in folder 4-1 (checkpoint, start, finish, etc).
FOLDER 4-5

Larger turn blocks like 4-5-4 and 4-5-5. And corner/turn blocks matching to 4-5-2! (
THIS is why)
FOLDER 4-7

Some matching border blocks for the blocks 4-7-1 and 4-7-5 (
image)
FOLDER 6-3

More decorative blocks like 6-3-6 and 6-3-7.