what is a good poke mage

vel'koz

Syndra is a great pick. She has good long-range poke if you can hit your qs and a full combo can half health somebody (q<e<w<q). And when you hit 6 you can all in with a q e w r ignite/another q. Once she has a lead shes hard to stop and has a wonderful late game if you play right.

Lux. She has a massive amount of utility and can burst down squishier targets as soon as a binding lands.

Ziggs is an option who doubles as a zone controller

Xerath was literally made to do exactly this.

has amazing poke, and you can finish someone off with 1/3 hp with a q ult while laning, not sure if that's what you mean by all in , however

Depends on what you're looking for, and what your team needs.

Long range poke:

Poke + strong teamfighting:

Poke/Burst:

Poke + utility:

Could give you some more poke mages, but minus the strong all-in potential

Syndra - I main her, she's great at all-ins and poke

Xerath - If you can hit skillshots his poke is deadly

Azir - He lacks an all-in until he gets an almost full build but his poke is as deadly as Xerath's

Cassiopeia - Can all in when the enemy is at 100% health and win without even using her ult

Karthus - Q is easy enough to hit and easier when his wall hits them. If they come close use E and when they are low enough just ult.