These are Chapters that I'm not too familiar with, as they are from other Forgeworld books rather than the Badab War. It seems they don't have quite the depth of coverage that the Badab Chapters have, but they do get their own Chapter Tactics.
The Angels Revenant were part of the Fall of Orpheus. They have the option to use Ultramarines Chapter Tactics or use unique Chapter Tactics to represent their Chapter after the Orphean Campaign. If they do so, the have Preferred Enemy and Hatred when fighting Necrons. When fighting any other army, they become Fearless when the detachment loses half of its units.
Honestly, this may be the most situational Chapter Tactics of them all. They’ll be great against Necrons, but becoming Fearless once half your units are dead isn’t going to win you many games. This is a very strange rule set; I can see what they were going for, but rules that only come into effect once half of your army is dead are not great (and that’s putting it mildly).
The Red Hunters are a Chapter with strong ties to the Inquisition. As such, the Marines have been hardened against Warp threats and repeatedly mind-scrubbed and psycho-indoctrinated. To represent this, all Red Hunters have Adamantium Will. Additionally, you can choose to activate their Mnemonic Redaction Protocols at the beginning of any turn. A number of units (including Dreadnoughts) equal to the turn number all get a chosen special rule until the end of that turn. This can be Conter-attack, Monster Hunter, Tank Hunter, Hatred, Skyfire, or Interceptor.
I really like this mechanic, as it can provide a massive advantage to your army for a critical turn. However, you get a better return the longer you wait, so you have to weigh the potential advantage of waiting against the losses that your force will take. If timed correctly, the Red Hunters will have one devastating turn with just the rule that they need.
Finally, Red Hunters count Grey Knights and Sisters of Battle as Battle Brothers as long as the army includes an Inquisitor. This is both fluffy and very useful if you are interested in allying with those armies.