Hundreds of easy to make paper models.
14. I’m a bit of an armchair quant, so most of my submissions are datasets, but there’s some other good stuff.
A catalog of just about every emulator that has ever been made. No ROMS, though. Make sure you only download ROM files for games you already own, kids!
Tons of game assets, from sprite sheets to sound effects. Some of the assets have licensing terms for use but most of the content can be used commercially as long as credit is given.
Quandl has a ton of data for free, most of the financial variety, but there is some sociological and psychological datasets in there too. Has an API for retrieving data for programs. Some of the datasets have to be bought.
Easily searchable database of SEC filings. Good if you like to research companies. Can export files as PDF, CSV, text, doc and a few others.
Tons of technical analysis for stocks for free. Also has a free API for financial data.
US Bureau of Economic Analysis. This is the agency that estimates GDP, unemployment, etc. All of their data and reports are published online.
A huge archive of mathematics paper with no paywall.
Organization for Economic Cooperation and Development. Lots of high-level data about the macroeconomics of countries.
16. OverDrive, Libby, and Hoopla. You can download free audiobooks and ebooks with the first two. Hoopla has books, tv shows, music, and movies. Most libraries use those services.
17. Unsplash is great for nice pictures you can use for anything.
18. Not downloads, but The Open University has loads of free courses where you can study different topics online in your own time.
19. myabandonware.com You can download over 14400 games for free, such as Doom, Wolfenstein 3D, Re-Volt, THPS 2 & 3, and many more!
20. pouet.net is a goldmine of demoscene experimental and art projects. Little projects by budding and experienced developers pretty much trying to refine their skills.
21. These are a few ones I’ve gathered on my web-dev travels.
23. This is one of my favorites. The New York Public Library has been digitizing material and it is now searchable. You can find great material that isn’t necessarily book. I’ve found old maps of the region, playbills, just general historical material that was kept but isn’t necessarily searchable in a regular way at the library.
25. Galbadia hotel has a huge archive of video game soundtracks to download.