Analytics Academy by Segment - Bite-sized lessons to become an analytics expert.
Google Analytics by SumoMe - The easiest way to see your Google Analytics
Ask GA - Get answers for your marketing questions based on GA data
Metric.live - Real-time and advanced periodic alerts for Google Analytics.
Marketing Resources List - The biggest collection of free marketing resources
Airtable - Airtable works like a spreadsheet but gives you the power of a database to organize anything. Sign up for free.