I have the hex drivers in the picture which came with no end cap - https://www.amazon.ca/gp/product/B08MTQKDQN. These are also all over AliExpress. I made this end cap to make it more comfortable to use. Also able to colour code them then!
The hex driver holder in the picture is https://www.printables.com/model/1013825-multiboard-hex-screw-driver-holder
The author marked this model as their own original creation.