(1/3)One of the problems of painting Blade guards badge is to come up with a good design for your chapter. Although Ultramarine has many good examples on box art, other chapters only have a few. I make a design sheet for you to make your own blade guards badges much easier:

(2/3) First step is to decide the overall layout of the badge. Since it's really small, I think a 2 cut design will be sufficient.
Second step is to find the color you want to use, usually it's your chapter's primary color and secondary ones.

(3/3)Finally, pick some icon or something meaningful to your chapter! I also love to have script on the badges. If you still cannot choose what to draw or transfers to put on, here's some very commonly seen elements:

Here are two examples I painted. The intercessor has a very simple design with only a red strip, indomitus mark and some scripts, yet it add more details to the overall model, making it more interesting to look at

For perfectionist: here's a blank design sheet for you. You can print it and draw some ideas on them before actually painting on the model. I hope this tutorial is helpful for you guys as always