Other High IQ Societies 

Quasar Quorum 

Quasar Quorum is an exclusive High IQ society open to those in the top 0.043% (at least 150 iq sd 15, 153 iq sd 16) of the unselected adult population. Mensa accepts those who score in top 2% of the unselected adult population or 1 in 50, you can think of Quasar Quorum as some kind of a super Mensa (I wouldn't use this name due to copyright) that accepts 1 in 2330.

Octopus High IQ Society

Octopus is another other High IQ society by Petros Gkionis. It is open to those in the top 0.39% (at least 140iq sd 15, 142 iq sd 16) of the unselected adult population. Mensa accepts those who score in top 2% of the unselected adult population or 1 in 50, you can think of Octopus as some kind of a a more exclusive Mensa (I wouldn't use this name due to copyright) that accepts 1 in 261.