I really liked the BLTouch covers this is remixed from (nice job). I added a side mount for an LED that I wired into the Raspberry PI gpio pin to control via Octoprint.

I used a 5mm LED from this set on Amazon. I used white, but you could use any desired color.
https://www.amazon.com/gp/product/B07FKKN2TC/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I put inline a 470 ohm resistor. I kind of wish i went lower but I didn't have a 330ohm I see recommended on line and was nervous about going to 220ohm (the next size I had on hand). Doing so though would make the LED a little brighter. You MUST have a resistor inline or you risk damaging the pi.