What are the isomers of C6H12?

https://en.wikipedia.org/wiki/C6H12

29??? Maybe.

If we limited it to straight-chained alkenes and any conventional cycloalkanes... (i.e. the reasonable ones that we would be expected to think of), then there are six. But let's just get as many of them down as we can think of.

Do you see how you won't be expected to know all of these?

(Note that R/S are omitted.)