Here is Bruder Ägidius of the 5th Gruppe 1st Gefechtskompanie. The Hellblaster Gruppe of the 1st Zug ( Platoon) .
And here is some more info about the Galactic Knights Chapter:
The Galactic Knights wear a completely white set of power armour. As the chapter is very old there are many different types of power armour in use at the same time. The latest is the Type X armour used by the Primaris marines of the Chapter. These are currently only deployed in the 2nd Gefechtskompaniekompanie.
The marines wear the Chapter icon, a black cross ( Krückenkreuz) superimposed by a yellow shield showing a black eagle on the left shoulder pad. The Krückenkreuz is the true chapter icon the yellow shield with the black eagle is the heraldry of the Germania system. It was adopted into the chapter icon after the Ordo Teutonicus chose its homeworld in the Germania System. So very old dreadnoughts might still show the old icon.
On the right shoulder pad the tactical sign in black is worn. These are like in the Codex Astartes.
The Gefechtskompanie is indicated by a shoulderpad rim in company colour. Here the Galactic Knights follow the codex astartes again but as the armour is plain white the 1st Gefechtskompanie wears black as colour. As the first is the elite company according to the Codex Astartes they wear black helmets instead of white ones, as all elite Marines in the chapter do. So the colors of the Gefechtskompanies are as follows:
1st Gefechtskompanie black ( also black helmets)
2nd Gefechtkompanie yellow
3rd Gefechtskompanie red
4th Gefechtskompanie green
5th Gefechtskompanie dark blue
6th Gefechtskompanie orange
7th Gefechtskompanie violet
8th Gefechtskompanie grey
9th Gefechtskompanie sky blue
10th Gefechtskompanie brown
As the Galactic Knights Gefechtskompanies are self-sufficient at all times they have their own Scout Gruppen. These wear the company colour broken by white stripes. There is no Scout Company and no support companies like in the Codex Astartes. The 10 Gefechtskompanies are similar to each other except for the 1st which is ,like in the Codex Astartes, the elite companie. The one with Terminator armour. The Galactic Knights amassed so much Terminator Armour that the complete 1st can be equipped as Terminators at the same time. The First Gefechtskompanie is also known as the Mondkrieger ( Moon warriors) . This commemorates that the Galactic Knights are the best void warriors you can find.
There are 10 Gruppen in each Gefechtskompanie these are designated by a cross in the corresponding colour worn on the right knee . Black for the 1st Gruppe, yellow for the 2nd, red for the 3rd, green for the 4th, dark blue for the 5th, orange for the 6th, violet for the 7th, grey for the 8th, sky blue for the 9th and brown for the 10th Gruppe.
All other insignia, like Terminator crosses etc, are like in the Codex Astartes.
The vehicles show the chapter icon, all other insignia follows the codex astartes.