Could be the archetype uncommon?

Seems to rely on scrying and the like to be reliable. If the card isn't a creature, you just payed 3 mana for nothing. Which is the same problem our original explore mechanic had. On the other hand, if the ability is reliable, it's a repeatable summoner that's an uncommon with the potential to cast 5, 6, 7 CMC creatures for 3 mana in the mid to late game.

This is also the multicolor slot that already has 3 other contenders. I'd want to see an explanation for why, say, Explorative Impulse or World as Will don't belong in the slot before considering new designs.

I'd like the multicolor uncommons to push you to play with the archetype, rather than just support it. With Bloodsap Elf and Explorative Impulse they simply get you more lands which, although it does work with discovery, could be played in a deck that doesnt really care about it. World as Will is better but I feel like we shouldnt have too many land animating effects, that starts to stray close to Zendikar. I'd like to see how the rest of the uncommons shape up before choosing that. I'd be fine with World as Will taking this spot but it doesnt particularly excite me.

This kind of effect doesnt need scrying or top of the library manipulation to hit reliably, Domri Rade was used in the deck for his -2. I'm assuming when you do this you'll have a decently high discovery.

Having such cards that force you to play the archetype are great, TRicher is correct in that. If you want to take up an archetype card in draft, it should force you a bit to also play that archetype, and not just take the card cause it is good on its own. I think this card is a little bit pushed, repeat summoner for 3 CMC is a bit strong. Still prefer this over World as Will and Explorative Impulse.