A buddy of mine asked me to convert and paint up two Sternguard, specifically as an Executioner and a Mantis Warrior. For the Executioner, I used the standard bits I use for my Marines. For the Mantis Warrior, I used Japanese inspired 3rd party bits. This harkens back to some very old fluff that presented the Mantis Warriors as broadly Japanese themed Space Marines.
Here you can see the Chapter Badges. I've got the Executioners badge down, but the Mantis Warriors is my first attempt. This is a difficult badge, and I don't thin I got the mandibles exactly as they should be, but otherwise I'm pretty happy with the badge.