All of these are just guesses.
Niche stuff:
- Lisp, in some form or another will continue to exist.
- Forth will continue to exist because it is possible for a single person to revive it.
Common stuff:
- vi/vim will live on. I will stop typing if it doesn't.
- JavaScript is probably here to stay.
- Java seems like a safe bet for longevity.
- Spreadsheets. Maybe not Excel, but spreadsheets will live on.