Ikora Rey is the vendor in Destiny 2 that deals with Vanguard Rersearch rep. She is located at the Farm once you unlock her in the story and at the Tower once you complete the game.
When trying to grind out Reputation for Vanguard Research Engrams it is wise to obtain and use a Ghost that will reward you with additional Vanguard Research Tokens upon completion of Meditations and Daily Milestone Challenges.
Ikora Rey accepts Vanguard Research Tokens in exchange for reputation points. 7 Tokens will be required for a full level of Reputation. Once you have handed in 7 tokens you can collect your Faction Reward which will show in her menu as a Legendary Engram. You can get one or more of the following items from each engram you collect from Ikora Rey:
- Faction Helmet (Class Specific)
- Faction Gauntlets (Class Specific)
- Faction Chest Armor (Class Specific)
- Faction Leg Armor (Class Specific)
- Faction Class Item (Class Specific)
- Legendary Shards
- Misc armor pieces and weapons in a shifting lootpool
You can check the exact stats of the items or what is currently in the shifting lootpool by pressing or on the Faction Reward Engram while speaking to Ikora Rey.