My aim here was to control the functionality of transports without necessarily fully reproducing the mechanics. A whole column of the warscroll is taken up here by the Transport rules. I've restricted the occupants to Imperium models without the Vehicle or Monster keywords. This allows Imperial Guard presumably or Inquisition to use Razorbacks as well since it's kind of a generic transport, usually used by astartes, but available for other factions as well. I'm going to give bikes the Vehicle keyword, which means that they won't be able to embark in transports. This does leave Assault Marines and Terminators who can't normally ride in Razorbacks able to do so, but my feeling is that simplicity is more important than that detail. If someone really wants to load their Terminators into a Razorback, it's not going to break my heart.
The next warscroll on the agenda today is the Techmarine. I was thrilled to discover that Techmarines can finally live up to their fluff of being Priests of the Cult of Mars. I pilfered some Priestly mechanics from the War Priest of Sigmar, and restricted their targets for their prayers to Vehicles and Cult of Mars models. This way, they can repair vehicles with the Blessings of the Omnissiah as well as synergize with Servitors and hypothetically with Adeptus Mechanicus models.
On the note of Adeptus Mechanicus models, here is the warscroll for Servitors.
Nothing too exciting here, but I thought I'd share them just to complete this subset of the Astartes faction. They follow up on the Tactical Weapons theme of the Astartes, but are clearly less impressive with their single wound and low bravery. They also have Mindlock, requiring them to stand next to a (typo) Brotherhood of Mars Hero, which I will change to Cult of Mars before I finalize my designs.