Resources for CBeam Router
Available from OpenBuilds. Numerous options available. Look at the WorkBee and LEAD bundles for larger footprint machines. Also, similar machines can be found on eBay/Amazon/Ali.
Teensy Breakout Board
Available from Brookwood Design on Tindie. Uses a Teensy 4.1 from PJRC.com. Some assembly required.
NEMA23 Motors. 175 Ounce/Inch Torque. Higher would be OK. Widely available on eBay/Amazon/Ali.
TB6600. I bought these a while ago and they don't seem to be available any more. The newer style will work - DM542 (or clones) will work. There are many other less expensive drivers that will work as well. I have the motor current set for 2.0A but select a driver that supports 2.5A at minimum. Widely available on eBay/Amazon/Ali.
Also note, you will see TB6600 drivers available on eBay/Amazon/Ali but be aware these are almost all fakes and don't use the TB6600 chip. You can tell because they claim to have 1/32 microstepping which the TB6600 does not have.
24VDC 14.6A Power supply - Meanwell LRS-350-24. Widely available. 24VDC to 12VDC stepdown converter for relays and 0-10V output. This has a handy display for adjustment.
grblHAL running on the Teensy 4.1. Open Source. Uses IOSender on a PC. Also Open Source.