Requesting more dark skins for most common parts
I generally use the orange/charcoal skins on parts when building rockets, but I do mix it up here and there, and I'm very regularly annoyed by the glaring ugly tubes which cover the engines when decouplers are attached to them, as well as the ugly looks of decoupler rings themselves, large RCS tanks, pods, and other common parts which all look garish when used with orange skins on other parts of the rockets.
There's also the S4 line which has no orange skin options, I guess because you want them to always look like an Atlas V or something, but it's still annoying to build a fully orange ship covered in an orange fairing, with a boost stage of fully orange S3 tanks, except for the one updside-down s4-adaptor at the top of the boost stage, which is very functional for stability upon re-entry and recovery of the booster stage, etc, etc, but is super ugly in black and white next to all the orange of the ENTIRE REMAINDER OF THE ROCKET...
Of all people in the world, the KSP devs should understand that when you give players parts in this game, we're going to use them in the most obvious ways, as intended, and then we're also going to use them in the strangest, most unintended applications imaginable, and we're going to make some really weird, cool stuff with them that goes far beyond what the average NASA guys of the 60's were doing with them. This means we will need more color options than the ones for the "intended" use of the part in order to work with our other crazy contraptions. This is the essence of KSP. It's just stupid to not make parts like these compatible in color with all the other parts which totally do have color options.
Good skins make sexy rockets. As it stands, my rockets usually look more like something I put together with parts I found at a garage sale due to all the horrible color clashes which have no options to change them. Sometimes it's charming, but sometimes I actually want to build a really cool rocket, ya know? And black and white doesn't qualify as "really cool" in this century. I don't make YouTube vids from my play time and I don't care enough to spend hours putting custom flags on ships to reskin them, but when I do my best to create something cool and unique and end up with something very bleh and generic simply due to junky color schemes of the required parts, it kills my drive to fly the craft or bother trying to create anything like it again.
Also, why can't we have skins for plane parts? White space planes are boring. I can get a bit of color by adding inline rocket fuel tanks in the wings, but the looks of planes are just way too vanilla and don't have enough options to make them feel like a personal creation. No matter what you build from plane parts, it feels more like a generic cookie-cutter design than your own thing. They look totally out of place, boring, and ugly next to the line of ships I've created over time, and this stops me from using the parts on anything but planes if I can possibly avoid it.
Basically, I would like to see every possible part which has no orange skin have an orange or charcoal skin to at least fit in with the darker color schemes available in the game, especially the most common non-fuel-tank parts like RCS tanks, reaction wheels, decouplers, pods, cargo bays, etc.
TLDR: Please give us more dark-themed skin options for all the things! And if you're feeling generous, how about some other colors like a sporty blue?