There are 26 items needed for this achievement. So far, I've crafted 3 items while playing in my most recent session, but only 2 of them counted for the achievement.
I've crafted the following:
Crafted Bow, Fire Arrows, Molotov, and possibly Bone Arrows. It's likely the Molotov and Crafted Bow that counted for the achievement for me.
The full list of craftable items and their requirements can be found on the official wiki.
https://theforest.fandom.com/wiki/CraftingKorra II.