Legacy or MotM Toggle Option in Monster Search

The Monster search there should be some sort of option that allows users to exclude MotM content (or put another way, only see the 'Legacy' versions of monsters) without having to add everything non MotM to the source box. Perhaps this could be a toggle option or a three option drop down (Both [Default], Only MotM, Only Legacy).

My searches are now ridiculously cluttered with results I don't have access to.