Icons
- Eva Icons: MIT
- Clarity Icons (MIT License)
- Feather Icons (MIT License)
- BallIcons (Commercial, not FOSS)
- Glyphish
- IconBros: Nice icons for commercial use
- DevIcons: Icons for programming languages and tools (Java, Atom etc)
- FontAwesome: SVGs and iconfont
Illustration
- Undraw: open source (no-attribution) illustrations
- Lorum Ipsum Illustrations: By Marie Schweiz. MIT license
- Drawkit: MIT and commercial art
Sounds
- AppSounds
- Files.design: Another list of sounds usable for apps
- Scott Buckley Library: Longer tracks, probably most useful for videos etc
- Bosca Ceoil: Sound generator
- No Lick: Royalty Free Music
- (Nichemusic)List of 12 links for free audio
Patterns/Inspiration
- Mobbin: Mobile design patterns library
Other Resources
- Design Sprint Kit: Google provided resources for running your design sprint
- Creating Design Systems