I kind of started accidentally with Michael Harris, then found out about Sam Herman coming over to the RCA in '67, and his influence - so anything from the RCA circa '67, or early Mdina and IoWSG, up to about the mid-70s.
But as with any research, the more you find out, the more you find out there is to find out...
I like Eisch and Motzfeldt, I've been tracking down the "story" of Malta Decorative Glass and how to identify it.
Sort of the more European arm of the Studio Glass Movement, although I have some interesting American early bits too.
I'm also quite into several contemporary artists' work.