Does Spell Vamp affect magic damage procs from items?
Solution 1:
The Spell Vamp portion of the LoL Wiki and my own experience show that
[Spell Vamp] works off of activated item effects, summoner spells, and abilities, regardless of the type of damage done.
Therefore, items that give proc effects to attacks like Bloodrazor, Wit's End, Malady, Wriggles etc, will NOT grant the user health through spell vamp.
On a side note, Ezreal's Mystic Shot (Q) applies on hit effects, including but not limited to, lifesteal.