SocialSizes - Sketch templates for sharing images & videos on social media
PixaPal - Create videos, graphics and documents online
Startup Booster - Startup Booster is a pack of 27 stylish creatives for social media.
Graaphics.co - Create easy, effective graphics for your social media. Choose your background, size, fonts, colors and text, and quickly export your designs, ready to post to your social media channels. Perfect for testimonials and quotes.
Instagram Story Templates by Kapwing - Create simple, beautiful Instagram Stories from templates
GIMP Online - Powerful graphics editor in the cloud