Here's a couple:
When you eat a champ for the kill
After you've been killed, but you nail the enemy for a kill in plant form
Full combo (or any combo) dropping enemy from 100-0 before you can even blink
Hitting 5 people with any spell, easiest done with:
Getting a harrier mark + IE empowered shiv crit with 
. Goodbye health bars.
Flashing forwarding and getting the last hit with the last auto to get a kill with 
Dying as 
, but knowing that a stray shroom killed your victim that was ready to rush at your team to kill them.
Landing a long range skill shot killing your low hp enemy with no vision. That time I did support vel'koz and threw a Q killing Jinx in the far back.
Baron steal hands down.
I have two favourite ones.
(prerework) goes to 1 v 5 the enemy team giving me vision of baron, I 
ulti over the baron wall smite steal mid air, land my AoE helps get a penta. one of my favourite league moments.
and I literally walked up and ate baron right in front of them.When Ezreal tells me he loves me <3
