A, B, C: Special cases.
F: Fairies (unlocking things)
J: Locking? (Gamble nest). No idea on name.
K: Healing stuff, per the bullets. "Knit" maybe?
L Corp: Duh (formerly smoke?)
M: Moonstones, special protective rocks
N: Only know some of its nest rules like no recording stuff from DD
U: Not-time. That is, stasis stuff. Name: ?
W: I feel the Warp overtaking me. It is a good pain.
14 is a good call. Notably X, Y, and Z are unknown and they're the other bookend to A, B, C so maybe that will go somewhere.