Invision — Prototyping, collaboration & workflow platform.
Coolors — Generate infinite color palettes for your designs and share, export or save it in your profile.
Beetle Blocks — Visual code for 3d design.
Vikalp Design — Great project that designs cultural communication symbols.
impress.js — Presentation framework based on the power of CSS3 transforms and transitions.
Placeit — Free product mockups & templates.
Best Pitch Decks — Good pitch deck resources and examples.
PSDTUTS — Free tutorials in design and illustration, 3D, motion graphics, photography, and audio.
GIMP — GNU Image Manipulation Program. Graphics software for photo retouching, image composition and image authoring.
Microsoft Inclusive Design — Microsoft's very good center that has a lot of great resources for designing with inclusion in mind from the beginning.