Echo of Eons
50PlayableSorcery
Modern Horizons
2HG Rating
50/100
Plays about the same in 2HG as it does in any other format.
No 2HG-specific rules fire on this card — it plays much the same here as anywhere else.
Ratings start at a neutral 50 and are adjusted by rules derived from 2HG's structure — shared 60 life, shared turns, two opponents. They'll be recalibrated against real play rates once teams start submitting decklists.
Oracle text
Each player shuffles their hand and graveyard into their library, then draws seven cards.
Flashback 
(You may cast this card from your graveyard for its flashback cost. Then exile it.)
Legality
Plays well beside it
Fits the same colour identity — good candidates for your teammate's deck.
Suggestions are characteristic-based for now. Once teams submit pairings, this becomes a real co-occurrence score: played in X% of teams whose partner deck runs Echo of Eons.