Cyberpunk fashion has you covered.

"Grayman" is a fashion concept built around high-tech low observable looks. It's exactly what you're talking about; All the cyberpunk high tech fashion and utility, but with an aesthetic that is unobtrusive and doesn't draw attention, or even goes further in trying to exploit human psychology to make you less noticeable than the average person on the street. They actually quote Gibson in the article!

My adventurism kit is built around the idea; Wear really basic, boring stuff on top so no one pays too much attention to what's in your bag. And it's reflected in modern attitudes on bloc - The leading wisdom is that bloc is no longer desirable, and the goal should be wearing unobtrusive clothes so you can move separately without attracting attention from the security forces, then converge rapidly on one point. If you're in bloc everyone knows who you are and what you're doing. If you get separated from the bloc there's a very good chance you'll be targeted, arrested, or snatched. If you're wearing normal, deliberately unobtrusive clothes without identifying features like distinctive shoes or logos it's much harder to keep track of you whether you're in a crowd or on the street. Grayman often leans in to the fashionable aspects of that idea, but you can apply it practically, too. Something as simple as having good quality socks and underwear can make a huge difference on a 10 mile march in hot, muggy weather.