For a long time, the website “Warpath”, which shows the various monster sets you’ll encounter in rifts and gives their progression values, sat dormant. I think its creator, Silec, was away from the game for an extended period.
But, he’s apparently now back, and the website has been updated. The most noteworthy change is updated figures on progression for a ton of mobs. Some of these changes are modest, but others are substantial (for instance, Spine Lashers are now worth 7x as much progression as they once were).
I’ll caution you here that, like I said, the website hadn’t been updated for a while, so before you jump to the conclusion that this or that mob type is now great, it may be that you’ve been playing against it with increased progression for some time now, and it still feels terrible.
Anyway, the updated site is well worth a look: News - warpath