Phyrexian Rager is a great card and this is basically superior in every regard except in the most aggressive of situations
The trouble is, of course, that you can only run Contract From Below if you're playing for ante, i.e
While I suspect that Jund Saga plays too many one-mana spells to effectively support more than one copy of Ziatoras Proving Ground, I bet one makes the cut
In addition to gods, there are a lot of heroes and monsters
Your clues can be sacrificed to their own effect, or to enable a card like Deadly Dispute, either way your Tireless Tracker will be gaining some counters
This is where Teferi, Hero of Dominaria, earns his reputation by turning time itself into a resource