FameBit - Easiest Way to Find, Hire, and Work with YouTube Influencers
Kalam Labs - Twitch for Science
inzpire.me - An end-to-end solution for influencer marketing
MathCrunch - Learn math stress free
Insense & Paid Media - Find creators for short-term and long-term partnerships
Code Fight Club - A fight club you can talk about. Less punching, more coding.