Guns cars, planes exist but pre-Internet so information isn't globally shared in a split second.
So then information "technology" is going to be at a premium.
Anything that can simulate a computer, as well as anything relating to encryption, is going to be at a premium.
You're in a city under martial law that's declared it's hatred of your kind. Maybe your D&D powers violate laws, maybe a previous transplant raised an army of undead, who knows (or cares). The the vast majority of locals will turn you into the authorities who will imprison and study you assuming immediate off-the-record execution isn't an option.
That means alter self is going to be critical, probably why druid got banned. Other alteration abilities, up to outright shapechange are going to be similarly valuable.
The thing is, once you've escaped, they decrease in value; UNLESS . . .
But there is a win condition, if you take over a country with the military might and inbred hatred of your people like Nazi Germany, you can flip the local region back to friendly. In such a case you need to prove to them you're a productive member of society and not just built for war. So what would you offer to the job market?
This seems a bit confusing:
I have to take over the country I am in?
Why not just a neighboring country that is stronger?
Meanwhile, why exactly do I need to prove I'm of value other than in war? Don't they have other enemies that need destroying? Clearly I could help with that if I'm purely spec-ed for war.
Of course, that skips over the much simpler solution: remember those alteration, aka "shapechanging" powers that become obsolete when I escape?
Well . . .
I don't escape; that is not my plan.
Never mind killing Hitler, I will to "replace" Hitler, as "Hitler".
Or as Himmler or Goebbels or Bormann or Goering if I must settle for "inheriting" things. (Based on the usual factors and all that.)
Depending on how quickly I can manage that, I can switch "extermination" to ""subversion"/incorporation", or just "expulsion" (go Madagascar Plan!).
Well, unless I simply don't care about my people, in which case, whatever.
If it is too late for my people, then you can just call this the "Riddick Plan" - become Lord Marshal and retire to the battlefield.
I'm thinking something along the lines of a Beguiler here, with some telepathy based prestige class, and some shapeshifting feats.
You'll have your skill monkey for deception and subversion, your illusion powers as a fall back for your shapeshifting, and your telepathy for more subversion and communication.
Overall, just go at the whole thing sideways instead of frontal assault on the problem.