Some obvious examples
- the holodeck gets a fatal software error and people are stuck in a classic novel
- a shuttle breaks down and crashes into a habitable planet
- the federation loses a space battle, but thankfully there’s some space jungle (nebula, asteroid field, etc) to hide out in, thankfully within sub light distances
Way too many actual WWII nazis. I think they are in every series, except DS9. But that one has its own version.