Dark Sphere + Szarel, Genesis Shepherd Combos

Combo 1 with Evolution Witness

Steps

1. Activate Dark Sphere by tapping and sacrificing it.
2. Szarel triggers, putting a number of +1/+1 counters equal to its power on Evolution Witness.
3. Evolution Witness triggers, returning Dark Sphere from your graveyard to your hand.
4. Resolve the Dark Sphere ability.
5. Cast Dark Sphere by paying {0}.
6. Repeat.