I'm kind of an audiophile person and there are some sound effects and voices I enjoy everytime I hear them. But until now I never thought about giving some positive feedback for that!
Eterum Nocturne (best ones are the R and E), Pulsfire Ezreal (especially the power level taunt!), Threshs W
Fiddlesticks (everything), Nocturne (R and E again), Ahris passive orb sound, Oriannas R, Morganas E, Evelyns R, Nautilus' R, Leonas R
Remarkable voice acting:
Nocturne (with and without legendary skin), Nidalees war cry (female war crys that sound genuine and not mannish are extremely rare), Kog'Maw (I don't know, he just sounds like the demon maggot he is)
Jayce (I'm going to enjoy this! ), Nasus, Renekton, Lulu, Teemo (don't hate me), Kennens war crys when he uses W, E or R
I bet I forgot something important.
Thank you for that awesome work!