Trilium Notes - Trilium Notes is a hierarchical note taking application.
Quick Code - Curated list of free online programming courses
Hackr.io - There are tons of online programming courses and tutorials, but it's never easy to find the best one. Try Hackr.io to find the best online courses submitted & voted by the programming community.
Google Keep - Capture notes, share them with others, and access them from your computer, phone or tablet. Free with a Google account.
Slip.so - With Slip you can monetize your programming knowledge. Build engaging and interactive programming courses for your audience
STUDIO - Next generation design tools for digital products.