Customizable light bar for LED strip lights. I attached it to my Ender 3 V2 with two of the M5_System20_Bracket_40mm_Single_Sided_Square brackets from this collection:

https://www.thingiverse.com/thing:2957550

But you could attach this bar to anything you can bolt a bracket to.

This LED light strip I bought from Amazon, but any should work as long as they fit inside the light bar channel, which is adjustable:

https://www.amazon.com/gp/product/B07CVRVPRM/

I originally put a strip of LEDs in the cross bar channel (visible in one of the photos) but the light was somewhat blocked by the hot end and X axis trolly so I added these.

The largest bar I could print in one piece on my bed was 225mm wide and 60mm deep. That seems like a good fit for my needs.