The best place to get regular tumblestones is the starting area in the obsidian fieldlands, the aspiration hill and horseshoe plains. This is because no other types of tumblestone have been unlocked yet so every tumblestone is regular. Sly tumblestones are common around mesprit’s lake in the fieldlands, and there is also a cave underneath the waterfall near your second bass camp in the alabaster icelands that has three. There are quite a few black tumblestones in the oreburrow tunnel iirc, and that’s also a great place for iron chunks. There are a few black tumblestones on the way up to deertrack heights, and some more black tumblestones on the plateau in the coronet highlands where the alpha steelix is.
