How do i know which class i can or cant use for each platform?

Hi all, I am new to Monogame.

How do i know which basic class i can or cannot use in android / ios / Linux / Mac ?

Classes like …

System.Math
System.Threading
System.Data
System.IO
System.Whatever

Thanks.

This should give you a good idea http://scan.xamarin.com/

Are there any other ways ? Like IDE gives you warning or AutoComplete wont show it … Technically i dont want to know it after i finished coding =) Thanks.