Vex Runes explained
There's one set of runes for Vex on patch 14.23 that is the clear favorite for LoL players and pros alike. The best Vex rune paths on the position 
Mid are 
Domination as the primary path and 
Sorcery as the secondary path with a pick rate of 74%. Besides picking runes on Vex you should learn how to play Vex and if you are interested in pro matches take a look on how a pro builds Vex. If you want to discuss 
Vex then you should visit the champion subreddit.
Vex runes from primary path
Domination improves burst damage and assassination tools on Vex. Most of high elo players – and our LoL pros in the the major regions – have agreed that 
Electrocute is the best keystone rune to run on Vex. This keystone rune provides burst damage, aiding them in nuking down the enemy carries. Other primary runes on Vex are 
Taste of Blood, 
Eyeball Collection and 
Ultimate Hunter.
Taste of Blood heals Vex as soon as you damage an opposing champion. Eyeball Collection is next up. This grants the user additional damage with every killing they score. Ultimate Hunter scales up Vex ultimate haste on every unique champion takedown.
Vex runes from secondary path
When it comes to your secondary path, most Vex players prefer to go with Sorcery. Sorcery empoweres abilities of Vex and increases the available champion resources. On the Sorcery path, the best runes for Vex are 
Manaflow Band and 
Transcendence.
This is usually followed up by taking Manaflow Band for additional mana and mana regenaration. Transcendence for some more Ability Haste.
FAQ for Vex Runes
Which is the best keystone rune on Vex?
The best keystone rune on Vex is Electrocute. This Vex runes setup is then referred as Vex Electrocute.
What runes does Vex use?
Runes from the paths Domination and Sorcery are the most used runes on Vex. For the exact pick rates of Vex runes used, you have to study the rune distribution presented.