Gridfinity basic building blocks, fully parameterized to support any grid size.
Uses grid specifications from Zack Freedman, except this allows the grid size to be altered. Zack's move to make this open source is great, but I personally didn't care for the 42 mm grid size, prefering Alexandre Chappel 55 mm size. And Zack's project broke when using a different grid size. I also spent a fair bit of time cleaning the components up and parameterizing it.