Draft Commanders (Casual)

Azorius (UW) – Mechanic: Addendum – Instant spells that gain a bonus effect when casted in the main phase.
Gruul (GR) – Mechanic: Riot – Creatures can enter the battlefield with a +1/+1 counter or haste.
Orzhov (BW) – Mechanic: Afterlife – Creatures generate 1/1 flying token(s) when they die.
Rakdos (RB) – Mechanic: Spectacle – Spells become cheaper or add an effect if your opponent took damage that turn.
Simic (UG) – Mechanic: Adapt – Creatures can buff themselves with +1/+1 counters, but only if they have no counters yet.

Boros (RW) – Mentor Mechanic (Mentor creatures attack and provide a +1/+1 counter to a weaker creature).
Selesnya (GW) – Convoke Mechanic (Tap your creatures as mana to play convoke spells).
Dimir (UB) – Surveil Mechanic (Scry except send cards to your graveyard instead of the bottom of your library)
Izzet (UR) – Jump-start Mechanic (cast spells from graveyard by discarding a card). 
Golgari (BG) – Undergrowth Mechanic (Undergrowth cards get a bonus based on the number of creatures in your graveyard).