Some old style organs that are not "well-tempered" have split keys for some notes, so that you can choose D# vs Eb (for example), depending what else is going on.

I'm sure I've see on here something that does not just that, but also remembers what it just did so when you play your next notes it doesn't jump to a different tuning.

There are also digital keyboards that let you bend pitch after you hit a note by shifting the pressure similar to a violin.