...
- a, b, c, d, e for terrains
- f, g, h, i, j, k for crossers (if there are streams they are most likely g, roads h and walls i)
- l, m, n for extra terrains
- o, p, q, s, t, u, v, w, x, y for groups and features
- z for edge tiles
- r for either groups or terrain
(Thanks to Zwerkules and Dafenatotally not Dafena on the vault discord)