Landing Pages in MailChimp - Easy to build, custom landing pages for free
TopStartups.io - Backed by investors like Sequoia, A16Z, Benchmark. See the fastest growing startups in one place.
Landingfolio - The best landing page designs for your inspiration.
Gemoo Snap - A free "Swiss Army Knife" of screenshot tasks for startups.
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Startup 101 - TL/DR: Curated startup lessons for entrepreneurs who are looking to start a company as well as those in the process of building one.