Selesnya

Selesnya: Convoke- (Only returning mechanic)

Dimir: Surveil- Surveil is like scry but instead of putting on bottom of library, you put it into your graveyard.

Boros: Mentor- When a creature with Mentor attacks, you put a +1/+1 counter on an attacking creature with less power.

Golgari: Undergrowth- Undergrowth abilities care about the number of dead creatures in your graveyard.

Izzet: Jump-Start- You can cast instants and sorceries with Jump-Start from your graveyard by discarding a card, paying the mana cost and exiling the Jump-started card.