Interfacer - Collection of more than 200+ free design resources
SocialSizes - Sketch templates for sharing images & videos on social media
Facebook Design Resources - A collection of free resources made by designers at Facebook
Online Video Templates by Pixiko - Discover stunning free video templates, pick and edit
Freebiesbug - Collection of the best free web design resources.
Instagram Story Templates by Kapwing - Create simple, beautiful Instagram Stories from templates