An ability of the equipped creature or an emblem you own that triggers when a creature "leaves the battlefield" will trigger twice if that creature leaves the battlefield by dying
There are 5 common, 5 uncommon, 6 rare, and 5 mythic rare SPE Welcome Deck cards
There are MTG cards that cost as much as a bag of chips or crisps, depending on where you are from
Remember, these cards care about how much mana you actually spent on the spell, not the printed mana value so the higher tiers of Ice Magic and Thunder Magic, the flashback casts of Dreams of Laguna and Laughing Mad, and a big Syncopate or Choco-Comet will all work to trigger your stuff
The next step is to think about where black and white overlap with one another, and capitalize on that
And when you do manage to gang up and kill him, it's not like the Commander tax on a 3 mana leader is overly prohibitive to replaying Leo