Tool to find influencers in a niche?

I am new to a niche and aren't aware of the taste-makers in this niche.

What are some tools and processes to figure out the top 100 influencers I should focus on?

Is there a way to rank influencers on a "most likely to respond" score (similar to the way OkCupid puts a score on their users)?

There are few apps which can help you find influencers, but none can show you who are "most likely to respond". OkCupid is able to show that metric because all communication is on their platform. In your case, most communication is done via email, so no tool is going to know which person responds the most.

The two best tools I like to use:

• BuzzSumo
• FollowerWonk
• Twellow