387 cards.
EDH Seer reads the oracle text of every card in a Commander decklist and reports which pairs actually work together, with the reason printed next to each one.
Edge. When a creature enters thanks to Krenko, Mob Boss, Impact Tremors deals 1 damage.
No edge. It wants a creature entering, and a fetched land is not one.
Ramp, removal and card draw are roles, not synergies — they make a deck work without pairing with anything, so they are counted as slots rather than drawn as edges. A card that refers to itself ("this creature", "this spell") is read as itself and not as a class. Where the rules cannot say something, the report says nothing: a missing claim is better than a confident wrong one.