Zed Runes explained
There's one set of runes for Zed on patch 14.12 that is the clear favorite for LoL players and pros alike. The best Zed rune paths on the position 
Mid are 
Domination as the primary path and 
Sorcery as the secondary path with a pick rate of 33%. Besides picking runes on Zed you should learn how to play Zed and if you are interested in pro matches take a look on how a pro builds Zed. If you want to discuss 
Zed then you should visit the champion subreddit.
Zed runes from primary path
Domination improves burst damage and assassination tools on Zed. 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 Zed. This keystone rune provides burst damage, aiding them in nuking down the enemy carries. Other primary runes on Zed are Taste of Blood, Eyeball Collection and Ultimate Hunter.
Taste of Blood heals Zed 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 Zed ultimate haste on every unique champion takedown.
Zed runes from secondary path
When it comes to your secondary path, most Zed players prefer to go with Sorcery. Sorcery empoweres abilities of Zed and increases the available champion resources. On the Sorcery path, the best runes for Zed are 
Scorch and 
Transcendence.
Scorch increases your control in the early game. Transcendence for some more Ability Haste.
FAQ for Zed Runes
Which is the best keystone rune on Zed?
The best keystone rune on Zed is Electrocute. This Zed runes setup is then referred as Zed Electrocute.
What runes does Zed use?
Runes from the paths Domination and Sorcery are the most used runes on Zed. For the exact pick rates of Zed runes used, you have to study the rune distribution presented.