How to make new variation for tiles?

     Let's say I made a draft layout of a top-down room and I have the same tile for the whole floor. Now I want to make variations like wholes, sand patches etc.
     The only way I know is super tedious and damaging to flow - make blank tiles for each intended new tile, slap it in place, then copy/ paste from canvas tile to new tile (or duplicate tile in tileset and still for each new I have to slap in canvas).
isn't there an option simply at least mark tiles in canvas to make new tiles in tileset?