Blitzcrank Runes explained
There's one set of runes for Blitzcrank on patch 15.14 that is the clear favorite for LoL players and pros alike. The best Blitzcrank rune paths on the position 
Support are 
Inspiration as the primary path and 
Sorcery as the secondary path with a pick rate of 72%. Besides picking runes on Blitzcrank you should learn how to play Blitzcrank and if you are interested in pro matches take a look on how a pro builds Blitzcrank. If you want to discuss 
Blitzcrank then you should visit the champion subreddit.
Blitzcrank runes from primary path
Inspiration opens creative opportunities on Blitzcrank troughout the match. Most of high elo players – and our LoL pros in the the major regions – have agreed that 
Unsealed Spellbook is the best keystone rune to run on Blitzcrank. This keystone rune allows Blitzcrank to create a one-time use summoner spell. The new summoner spell replaces one of their current summoner spells and remains available until it is used or replaced. Unsealed Spellbook has some unique rules in that a particular summoner spell cannot be selected again until three other unique spells have been taken. LoL pro players will often use Unsealed Spellbook to aid them in their current or upcoming situation. Are you about to fight the last dragon for a soul buff? Due to Unsealed Spellbook, Blitzcrank can choose 
Smite to help their jungler secure the dragon for the team. There are numberless circumstances where a particular summoner spell can turn the game on its head, and that's where Unsealed Spellbook shines the most. Other primary runes on Blitzcrank are 
Hextech Flashtraption, 
Biscuit Delivery and 
Cosmic Insight.
Having an extra way to decrease the distance with the Hextech Flashtraption will make an engage much easier to pull off. Biscuit Delivery is a great rune for laning as it gives additional health and mana, which can help in more aggressive lanes. Cosmic Insight grants summoner spell and item haste.
Blitzcrank runes from secondary path
When it comes to your secondary path, most Blitzcrank players prefer to go with Sorcery. Sorcery empoweres abilities of Blitzcrank and increases the available champion resources. On the Sorcery path, the best runes for Blitzcrank are 
Celerity and 
Nimbus Cloak.
Celerity boosts all movement speed bonuses to Blitzcrank. Nimbus Cloak, which grants movement speed upon using a summoner spell, works amazingly well with junglers in particular as they take the shortest cooldown summoner spell, Smite.
FAQ for Blitzcrank Runes
Which is the best keystone rune on Blitzcrank?
The best keystone rune on Blitzcrank is Unsealed Spellbook. This Blitzcrank runes setup is then referred as Blitzcrank Unsealed Spellbook.
What runes does Blitzcrank use?
Runes from the paths Inspiration and Sorcery are the most used runes on Blitzcrank. For the exact pick rates of Blitzcrank runes used, you have to study the rune distribution presented.