Other than a swing wing, what types of variable geometry have flown?
Extending wings

The idea is to have a larger wing area at takeoff for more lift and a smaller wing area in flight for more efficiency.

The NIAI RK and followup RK-I used two tandem wings that served as rails for an extendable panel that could be rolled out between them.



The project failed because Stalin was so enthusiastic about it he had it use the most powerful engine available which was too unreliable. I can't find a reason why the concept was not tried again.

The German FS-29 glider of 1972 had a different arrangement. It had an outer wing that fit over an inner wing and could unsheathe like a sword. Only one was built.