Social Media Audience Tools
Narrow.io: Narrow helps you build a targeted Twitter following by making it effortless for you to interact with users who are likely interested in your product, service, cause or business. It’s quick and easy to use. Simply enter keywords or hashtags and we’ll identify a relevant audience for you and start building your following.
Snappa: A way to create custom post graphics in various sizes to use when pushing posts via social media. The service allows you to create social media sharing graphics for your posts with zero design skills required. It also keeps track of the dimensions used by the various social networks, so you're not having to constantly look them up before creating graphics to see if anything has changed. Snappa offers a free plan - no credit card required - so it's easy to sign up and play around with the service. If you move to a paid plan, it's $15 per month or $135 per year.
Picmonkey: Higher priced than Snapp with no apparent benefit. Stick with Snappa.
Thought Leadership Content
Buzzsumo - tool for determining what content in your niche is already popular across Facebook, LinkedIn, Twitter, Pinterest and Google+