More unique look to make it more than just reskin of X-03 Hellfire Power Armor from Fallout franchise.

Keep the colour pattern.
Just work with interesting shapes.

Maybe a faction? they could be like a awakened group of ancients from the base game, But maybe instead of just ancient soldiers they were a PMC? And could be a xenophobic nation thats raid style prioritizes in quality over quantity.

@Squire lord I have an idea for two factions so far. The first is a faction of awakened ancients all over the planet who have gathered in small groups around their shelters and who, according to the precepts of the vfe ancients, have a meme of isolationism and who are at war with everyone except other ancients. Their shelters would have been re-equipped for settlements from improvised materials. The second faction would be hidden, it would be the survivalist faction. these guys would have artistically modified ancient armor. according to my idea, they are lonely survivors from their shelters who are just trying to survive in the harsh world of rimworld

Sounds cool!

(Знаю что автор русскоговорящий, но дабы и другие поняли мое предложение, напишу на английском.)

The armor set of the operational intelligence group - the idea is to add an armor set that would be suitable for Ancient scouts, who, according to the idea, could go to the surface to collect the data needed by the leadership of the shelter. Well, for example, to act autonomously on the surface while performing some important task (For example, searching for a water chip, ahahahah) as an appearance, you can make something like a police armor from the Lonesome Road add-on for Fallout New Vegas. What is the special feature? Reducing the need for food and sleep, plus quite good protection indicators at the level of infantry vanilla armor.

An ancient psi inhibitor, a piece of clothing for the head that makes the wearer insensitive to psi effects, lowering psi sensitivity to 0. I think this is a pretty useful find for those who don't like the Buzz events.
And the opposite option is the psi accelerator, which, on the contrary, increases the sensitivity of the carrier by 100%, with positive psi noise for men or women, it is even useful.
As a reference for both hats, I think you can use the "medicine hat" of the psychic boy from the 188 trading post from FNV

A Hypno-Wave emitter. Yes, this is a hypnotron from fallout 3. Just a cannon that, when hit, imposes an effect that reduces the consciousness of the target, and has a small chance to cause small damage to the Brain (With a particularly unfortunate combination of circumstances, it is fatal.)
Just a cool almost non-lethal weapon for capturing prisoners.

@Евген Мяо It sounds cool, I'll take it into consideration.

You can improve or do little adjustments on the armor to fit games vanilla looking
Nice work though