OpenArms Core lifts a payload of one pound at 24" extension. No other open-source arm comes close.
It's all here: CAD files, source code, supplier lists--everything you'd need to build your own from scratch.
OpenArms modules are designed around inexpensive gears, bearings, and other components available everywhere. Electronics are 100% through-hole construction, too!
There are a lot of widgets bundled with Page Builder. You can use them to bring your pages to life.