TemplateMo - TemplateMo is a great place to get bootstrap templates from your website, which are all HTML5 supported with CSS layout.
HTMLEmail.io - Responsive HTML email templates for startups & developers
Ethereal by HTML5 UP - A fully responsive side-scrolling one-page HTML5 template
Mashup Template - Collection of beautiful free HTML templates
UIdeck - Landing Page HTML Templates and UI Kits
Inovatik HTML Templates - Download 24 FREE HTML templates to help you create beautiful websites and landing pages faster.