TemplateMo - TemplateMo is a great place to get bootstrap templates from your website, which are all HTML5 supported with CSS layout.
BotList - An app store for bots
Ethereal by HTML5 UP - A fully responsive side-scrolling one-page HTML5 template
ManyChat - ManyChat lets you create a Facebook Messenger bot for marketing, sales and support.
UIdeck - Landing Page HTML Templates and UI Kits
ChatBottle - Chatbots Search Engine