These are small PCBs for a variety of passive Eurorack "non-modules." I designed them to be under 1" in at least one dimension¹, so they can fit neatly under a strip of 1.5" aluminum angle (architectural angle, .0625" thick) — which makes for a perfect extra row in my Halliburton cases. If you wanted to, you could probably make a 1u panel for each of them. Or put a few of them vertically behind a single 8hp 3u panel. Or put them in a mint tin. Or whatever.
The circuits are all pretty simple, use only through-hole components, and the PCBs are all essentially 1 layer². Some of them circuits are based on designs by other Eurorack folks (who likely were inspired by others). For examples, see Yan's Patchpals, the Doepfer A-100 DIY page, and Synth Diy Guy.
I've included PNG images of each of the schematics, because I hate when I find Eagle projects on GitHub and have to clone them (and open them in Eagle!) before I can get a glimpse of the schematic.
The silkscreens don't necessarily indicate which side of the board to place to the component. You can decide which side makes the most sense for you. Obviously make sure the polarity matches what the silkscreen says though.
Labels and graphics are up to you, but I've included PDFs and AIs for each of the modules' holes. The AI files have separate layers for the hole dimensions, centered crosshairs, board dimensions, and name of the module. There's also a PDF of all of the panels on one page.
¹ The traces on the boards are all on the bottom layer, but practically it makes sense to have them fabricated as 2-layer boards. If you want to mill them as single-layer boards yourself, and you're willing to be creative with your soldering, you could do it.