Landingfolio - The best landing page designs for your inspiration.
TemplateMo - TemplateMo is a great place to get bootstrap templates from your website, which are all HTML5 supported with CSS layout.
Landing Pages in MailChimp - Easy to build, custom landing pages for free
Ethereal by HTML5 UP - A fully responsive side-scrolling one-page HTML5 template
Landing Page Checklist - Build your landing page with these 100+ tools
UIdeck - Landing Page HTML Templates and UI Kits