I really should wait to see if I get invited to your roulette first in case I want to use them.
I have no shortage of older stuff anyway though.
Anubis Gate is probably the best bet. Prog/power, not unknown, but they should be way bigger than they are given DTF's tastes.
Blackbriar and Delain are symphonic metal with female leads, among the better bands of their kind. A bit of harsh vocals in Delain, but not too much.
Karnataka is more neo-prog esque, female lead. Not far off something like Mostly Autumn or Magenta if you know them.
District 97 is kind of hard to describe, but it seems they're starting to blow up. Female lead, kind of art/alt prog rock/metal, quite interesting.
TesseracT and Soen are 2nd/3rd-tier DTF favorites that I would think you'd have at least heard something earlier from. TesseracT is djenty and has some harsh vocals, but not overbearingly so. Soen is more Tool-ish, but excellent.
Wytch Hazel is throwback hard rock/trad metal, Thin Lizzy-ish, one of TAC's favorites that I sent in his previous roulette.