Many DIY builders use Open Source CAD programs (KiCAD for one) instead of licensed programs like Eagle. It would be very nice if there where a KiCAD module and library of Sparkfun ESP32 Thing for us to use! There is a Eagle script plugin that may help converting your existing Eagle schematics to a KiCAD module/library: https://github.com/lachlanA/eagle-to-kicad
Could you please give it a try, since I don't have a Eagle license to try it myself.
Thanks!