they have no inherent effect
If you control Angelic Overseer and Humility enters the battlefield, Angelic Overseer loses all abilities including Indestructible
It can be played early on for its evoke cost as a removal spell, but later in the game it can be played as a hard-to-block creature that also gets the enter-the-battlefield removal trigger
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
Some rare cards use additional foil or holographic materials for special effects
In the usual rules update article for the set, some big changes to how Saga cards work in MTG have been announced