Landing Pages in MailChimp - Easy to build, custom landing pages for free
Google Design Sprint Starter Kit - This Kit helps you to run your first Google Design Sprint.
Landingfolio - The best landing page designs for your inspiration.
Nawvel - Nawvel is a handy-dandy library of tried, tested & curated resources.
SaaS Pages - 900+ Screenshots of the best SaaS landing pages
Design Files - Professional resources for digital designers