Base UI Sketch Framework - Huge set of everything you need to design and prototype
Vidrio - Holographic screencasting app for Mac. Free for COVID-19
INSTAD.IO - Automagically converts vector images into sketchy style
Scrimba - Interactive coding screencasts created in an instant
Sketch Extensions - An official collection of Sketch extensions & plugins
GoRails - Ruby on Rails screencasts for Web Developers