I've been digging in and doing some light research but I'm not quite there yet.
I know that Talon is one, and LeBlanc is another. They hinted at an AP assassin being included who I am almost positive is Akali.
Would the next one be Shaco? Or Rengar?
ModWulf Helhammer4 votesSo far we know Talon, Rengar, and LeBlanc
Reikken1 votesTalon, Rengar, LeBlanc, and Katarina
Sukishoo1 votesSo far only 3 (Talon, Rengar, and LeBlanc) have been revealed.
Akali on the other hand, most likely won't be part of it as they said she needs a full VGU and not what the class updates focus on.
SwiftKitten881 votesi hope to god it's 
. get rid of that toxic kit
Punchtown Hero1 votesI hope 
is getting a bit reworked, I like the ult and e but that q needs to change.
Hikokujin1 votesmaybe ekko, or fizz maybe even ahri idk
on the other hand is really more of a toxic champ.