I'd put Etali, Primal Conqueror above the others because its a better card overall
It offers the benefits we have already talked about with multiple ways to reset the burden counters (Teferi, Felidar Guardian and Otowara, but you can also -2 with Saheeli to make a copy of the ring and legend rule it)
MTG : Alpha Black Lotus and Beta Power Nine are leaders in value growth
-4 You get an emblem with "Your opponents play with their hands revealed" and "Whenever an opponent draws a card, this emblem deals 1 damage to them." Loyalty : 4 Legality Vintage Legacy Premodern Modern Pioneer Standard Duel Commander Commander Multi Historic Alchemy Illus
The creature that enters the battlefield doesn't need to have lesser power than Shadowfax (this can happen if it enters with +1/+1 counters on it, for example)
Beyond that it's mostly generic upgrades like Smothering Tithe, Teferi's Protection, better land upgrades, better removal, the usual