Alistar Runes explained
There's one set of runes for Alistar on patch 15.12 that is the clear favorite for LoL players and pros alike. The best Alistar rune paths on the position 
Support are 
Resolve as the primary path and 
Inspiration as the secondary path with a pick rate of 39%. Besides picking runes on Alistar you should learn how to play Alistar and if you are interested in pro matches take a look on how a pro builds Alistar. If you want to discuss 
Alistar then you should visit the champion subreddit.
Alistar runes from primary path
Resolve empowers the survivability of Alistar and increases the tankiness. Most of high elo players – and our LoL pros in the the major regions – have agreed that 
Aftershock is the best keystone rune to run on Alistar. This keystone rune bulks you up, increasing both armour and magic resistance, once you immobilized a champion. Aftershock synergises both with the sheer amount of crowd control Alistar possesses and the need to be tanky as soon as you engage. Other primary runes on Alistar are 
Font of Life, 
Bone Plating and 
Unflinching.
Font of Life provides your teammates with more sustain by healing them whenever they attack a champion whose movement you've recently impaired. Bone Plating make Alistar overall tankier, by decreasing the amount of poke damage in the early game. Unflinching inceases Alistar tenacity based on your missing health.
Alistar runes from secondary path
When it comes to your secondary path, most Alistar players prefer to go with Inspiration. Inspiration opens creative opportunities on Alistar troughout the match. On the Inspiration path, the best runes for Alistar are 
Cosmic Insight and 
Hextech Flashtraption.
Cosmic Insight grants summoner spell and item haste. Having an extra way to decrease the distance with the Hextech Flashtraption will make an engage much easier to pull off.
FAQ for Alistar Runes
Which is the best keystone rune on Alistar?
The best keystone rune on Alistar is Aftershock. This Alistar runes setup is then referred as Alistar Aftershock.
What runes does Alistar use?
Runes from the paths Resolve and Inspiration are the most used runes on Alistar. For the exact pick rates of Alistar runes used, you have to study the rune distribution presented.