mtg signet cards Rakdos | Dissension Foil | Modern Arcane Signet | Universes Beyond:

Keep the card advantage flowing, and you can maintain a steady supply of creatures to sacrifice for profit

Of course, these cards also have creature types that may be relevant for Modern

There are strong rumors of a new Hatsune Miku Commander deck arriving as part of Secret Lair, which could raise the stock of this Universes Beyond crossover when it is released

On the second damage step Blademaster deals one damage to a cunning opponent and on triggers resolution it will get its earned +1/+1 counter

The creative possibilities within those boundaries are genuinely wide open

On a related note is that when land subtypes were added, Illusionary Presence received a ruling stating "Can only give landwalk of land sub-types that exist (so you can no longer give 'Island of Wak-Wak walk')." Meaning that under the previous rules, you a) could give the Presence "Island of Wak-Wak walk" and b) people actually did so