To edit the source tiles in the Tile Palette window, use the Tile Palette Edit mode. In this mode, the Tile Palette window acts like a tilemapA GameObject that allows you to quickly create 2D levels using tiles and a grid overlay. More info
See in Glossary, allowing you to select, move, scale, and delete source tiles using the tools in the Tile Palette window.
Follow these steps:
Note: You can’t enable Tile Palette Edit for a tileset.
You can then do the following:
To delete the texture of a tile but keep the tile in the tile palette, select the tile in the Project window then press Delete (macOS: Backspace). Unity replaces the tile texture with a pink placeholder texture in the tile palette.