Changing tile/prefab/tilemap set probabilities (weighted random)
If you want to change the probability of a tile/prefab/tilemap entry being chosen, you can set different weights for each type entry in a set.
For example, here's a tileset with 3 different tiles, each with a different weight:
Increasing the weight will increase the likelihood of the entry being used. So in this example, the Grass 1 tile is most likely to be used whenever a Ground tile is requested, followed by Grass 2 and Dirt 2.
In order to use the weights, you need select the set in the project window and explicitly enable it for each type, as needed, by ticking the "Weights" checkbox. This enables the weight fields.
This is not enabled by default, because it's a bit more expensive to calculate, slightly impacting performance.