Which C# libraries are compatible with Unity Android or iOS

Is there a way to find out which C# libraries will work on Unity Android or iOS

Hmm… guide page is important, that means you need to check out what mono support, such as compatibility list, implementation list. What’s more, as Mono said they support WCF, but in fact, implementation is totally incomplete and many DLLs can’t be compile because of the well known JIT/AOT problem.
So I bet a good idea is import those libraries you need into a test project, build them for iOS(maybe with some test call) and if it works, then it probably also works for android (DONOT reverse this step).