Blind (Located: Sierra 117)
The arms of the player and the motion tracker disappear.

Cowbell (Located: The Ark)
Your explosives increase in strength.

Grunt Birthday Party (Located: Crow's Nest)
If you manage to get a headshot on a Grunt, the Grunt will explode with confetti and children will laugh loudly.

I Would Have Been Your Daddy (Located: The Covenant)
Unlocks new dialogue for the campaign.