Recently we had the 15 year anniversary of Expedition 1 of the ISS. That particular crew launched in a Soyuz (TM-31) and returned on a Space Shuttle (Discovery, STS-102), which I found a remarkable aspect for a space mission!
Which led me to wonder who else has returned to Earth in a different type of vehicle than the one in which they launched? After a little searching around I found that ISS Expedition 6 launched on a Space Shuttle (Endeavour, STS-113) and returned in a Soyuz (Soyuz TMA-1), but my quick superficial search didn't uncover anyone else. I thus tallied a total of six people from trips to the ISS.
The only other missions I found were Shuttle trips to Mir. For example it looks like STS-71 (Atlantis) picked up three Russian cosmonauts who had launched on Soyuz TM-21, and dropped off two at Mir to return on Soyuz TM-21. There are probably more, but I had no easy way of searching. So if anyone has an easy way to extract that information, maybe we can compile the full list? I've collected the ones I have found so far in a comment below.