Craftsy: Website that has thousands of craft related classes that are available to take, free or at nominal charge. Painting, sewing, embroidery ect.
https://www.mybluprint.com/

Open Source Tools (models available prediction year 2021):  The Open Source Ecology project will contain a list of 50 tools, all design files, that are deemed as the most important tools for civilisation to exist. You can download the plans, and find ways to build them, or take the plans apart to understand how they work. Project uncomplete, projected year of completion 2021.
https://www.opensourceecology.org/gvcs/gvcs-machine-index/

Instructables - open-source resource for makers, creatives where projects are documented in steps with parts lists, code, and open source files for laser cutting ect. Note- Some projects aren’t complete, or are of poor quality so proceed with discernment, carefully watching for any information is missing before getting all the parts to build.
https://www.instructables.com/

Make: Projects - Projects curated by Make team. Most of these will definitely work, but again, proceed with discernment before buying all the parts to build it.
https://makezine.com/projects/

Electronics- Great resource to use when working with, implementing and understanding an electronic component and how to use it in your circuits.
http://www.circuitbasics.com

Arduino Reference- Arduino’s reference database of all the functions that are in the IDE (This does not include functions native to libraries you have to Import. See the documentation that’s unique to that library for details on those functions)
https://www.arduino.cc/reference/en/