I was inspired by some synthwave stuff and wanted to make a retro-futuristic mod at one point, quickly gave up because what I was making didn't really fit my vision and I wasn't even entirely sure what my vision was.
here's what the palette I was using looks like.
here's the download link to a wad that contains the palette. if you do actually use this you'll have to make sure that you add the other 13 palettes that go along with it (all the different tints for when you get a rad suit and the screen goes green, or when things go red when you get damaged). you can do this in SLADE 3 by selecting the palette and clicking the "Generate Palettes" button, all the way on the right side above the palette.
here's a link to pk3 that has a similar palette and a few textures tweaked to that palette. all the game's sprites would need to be adjusted with this one though, because this one steals colors from other color ranges to make a new blue range.
when I gave up on my project I sort of started realizing that if I were to do a mod like this proper, it would take a decent amount of spritework to give it the atmosphere that I wanted... I guess a lot of the demons could stay as-is, but I think any zombie enemies could really use some tweaking to fit in with a retro-futurist environment, giving em cool uniforms and glowy visors, etc. weapons were a big potential issue too... maybe a mod like the Trailblazer could be adapted for this sort of project. anyway I imagine using something like what HazeBandicoot shared (and what IMX makes of it if that happens) would probably be more in line with what you want, though.