Feather Attribution - A free and tiny javascript library to track UTM tags, ref and referrer data client side so you can store these in your own database.
The Influencer Marketing Stack - Free resources to launch a killer campaign
LoyalAs - Get and track referrals automatically.
Content Marketing Stack - A curated directory of content marketing resources
ToneDen Lasso - Put fan and customer acquisition on autopilot
Mention ✪ Influencers Dashboard - Identify the influencers talking about your company