Teleport to altar
There are now keys for teleporting to up/down stairs - why not add altar to this
When trying to get (pre/post)crowned I tend to want to move to the altar a lot, or generally when reaching a level with a known altar. I suggest that '_' would teleport you to the altar in the same way as '<' and '>' now does for stairs.
One could expand on this even further, but altars was really the only thing I found that made much sense. Possibly '&' for a forge, since that's also pretty permanent.