Tile (tilemap) mask

on the tile (tilemap) is not possible to use a mask?

Currently, you would have to use a custom shader, or use multiple Tilemap objects to apply masks.

Masking could be considered, though do you mean a rectangular mask, or masking using a shape or transparent pixels from an image?

On the Tile I would like to use a mask from shape (graphics.drawTriangles), тo make a pie indicator.

Could you use Bitmap for this object, and Tilemap for the others?

Yes, the BitmapData version is already up and running.
For a certain convenience, I assumed that it is possible to set a mask for tiles.