[Airtable] UX Research Toolbox
[18F] Methods
[Austin Center for Design] Design Library
[Digital Gov] Usability Starter Kit
[Digital Society School] Design Method Toolkit
[dschool] Design Thinking Bootleg
[Google] Design Sprint Toolkit
[HyperIsland] Toolbox
[IBM] Enterprise Design Toolkit
[IDEO.org] Design Kit
[Microsoft] Inclusive Design Tooltkit
[Mozilla] Open Innovation Toolkit
[Usability.gov] Templates & Downloadable Documents
All About UX
Circular Design Guide
Design Practice Methods
Design Research Techniques
DIY Toolkit
Open Design Kit
Service Design Toolkit
The Toolbox Toolbox (lists a lot of toolboxes)