Karma Runes explained
There's one set of runes for Karma on patch
11.8
that is the clear favorite for LoL players and pros alike. The best Karma Runes on the position 
Support are Sorcery as the primary path and
Inspiration as the secondary path with a pick rate of 86%. Besides runes you should take a look on Karma Build and if you are interested in pro matches take a look at Karma Probuilds. If you want to discuss
Karma then you should visit the champion subreddit.
Primary path on Karma
Sorcery empoweres abilities of Karma and increases the available champion resources. Most of high elo players – and our LoL pros in the the major regions – have agreed that
Arcane Comet is the best keystone rune to run on
Karma. This keystone rune adds more damage to your abilities and increases your power in the laning phase. This is usually followed up by taking
Manaflow Band,
Transcendence and
Scorch.
This is usually followed up by taking
Manaflow Band for additional mana and mana regenaration.
Transcendence for some more Ability Haste.
Scorch increases your control in the early game.
Secondary path on Karma
When it comes to your secondary path, most
Karma players prefer to go with
Inspiration.
Inspiration opens creative opportunities on Karma troughout the match. On the
Inspiration path, the best runes for Karma are
Biscuit Delivery and
Cosmic Insight.
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.