Obviously these may be a miss for your format for other reasons (power, archetype mismatch, rarity, don't run planeswalkers etc) but here's a few that I found interesting, divided by broad category rather than color: While I'm still not done reading Cosima, God of the Voyage (I'm on chapter 2, the language is a bit dense) these cards are ones I do like both sides of
The center of high-value candidates is the Manga Rare series Among items in standard commercial circulation, the cards that easily become candidates for high prices are, as expected, the Manga Rare series
Pokemon expert site Serebii also note that there are multiple currencies in the game
If you do, exile target artifact or enchantment an opponent controls
A quick search on Reddit will get you a lot of ideas on how to use Leyline of the Guildpact in Modern, and we're sure that more broken interactions will find their way into the format as time goes on and people get to playtest this card