There is a cross tolerance between LSD and most other (all?) psychedelics. It generally works more in one direction than the other. For example, taking LSD first, and other psychedelics after, will significantly decrease the effect of the other psychedelic. But taking, say, mushroom or DMT first, and then LSD after, will not diminish LSD's effects too much. Mushrooms and DMT do not seem to have a cross tolerance with each other in either direction.