APPlyzer - Professional rankings & keywords for app developers, marketers and publishers.
Analytics Academy by Segment - Bite-sized lessons to become an analytics expert.
Segment Sources - Load CRM, billing, and other cloud data to your Warehouse
Ask GA - Get answers for your marketing questions based on GA data
App Annie - App Annie is a marketing analytics tool available for apps of all kinds. With App Annie, you can track sales, traffic, and a variety of other factors pertinent to monitoring an app's trajectory.
Marketing Resources List - The biggest collection of free marketing resources