Mana Crypt is a two mana boost on the spot, a fine addition to any combination deck, but its drawback is very real
"Vivi Ornitier is warping the Standard format and likely needs to go." On the other hand, Agathas Soul Cauldron might be safe for now, so other iterations of the Izzet Cauldron deck will still be an option
Explore is relatively similar to Surveil insofar as you get to choose whether to put a card on top of your library or into your graveyard, but only if it's a non-land
Commanders like Zellix, Sanity Flayer and Umbris, Fear Manifest can command effective mill decks
If drawn late, you get the immediate card draw
Being Rakdos-colored, this little Dragon can dive into the graveyard to cast Dragons, making any Dragon deck resistant to board wipe effects and non-exile spot removal, at the cost of the revived Dragon being unable to return a second time this way