Whenever you install any app, sideloaded or through the play store, it will give you list of permissions that it needs. So if you download a game and it says it needs access to your contact list or email, there is something fishy going on.
Also, the best thing to do here is the same as before: consult the reviews. If something is asking for permissions that it shouldn't need, it will get blasted in the reviews and the rating will get trashed as a result.