Tragic Slip to Stromkirk Aristocrat is a first turn must
Part sac outlet, part card advantage engine, June covers a lot of micro-synergies, which means it might sneak in as an enabler for certain niche strategies
None of the one drop or two drop "Tap for any color of mana" things are cheap like Birds of Paradise or even things like Noble Hierarch that taps for three are cheap either
We already know that Raya will feature in The Rise Of The Floodborn , so that opens up potential dragons Sisu, Amber, Jagan, Pranee and Pengu
It is as good for specific card quality but is substantially better for general card quality
I know that that's because the Delve makes it so you have a customizable Escape cost, but I think I'd be happier with the card if it had "Escape - , exile two other cards from your graveyard" or whatever