Forgive me if this is a silly question, but if there is one thing I have learned over the years is how important marketing is. This even includes politics as well, and the right weaponizes this to a scarily efficient degree. Politics becomes more than politics, but a form fashion itself. Think of how much of a selling point of "be one of us and you'll be cool and you'll get laid." CHUDs use.
So that leaves the question, what should we organize our optics around. What is the impression we want to leave on others?
Personally, I kind of like the Soviet aesthetic: Extremely cultured (as befitting of a largely internationalist ideology), hyper-rational, future-minded, egalitarian, hard working people. It implies that despite all the snobbery of fascists; they are the true decadents. Leftists are optimistic about the future, and know that no race or gender is superior to the other because that is simply common sense. Cuban aesthetic is nice too because of how fun and inviting the country looks too. Say what you will about cars, but there is a lovely aesthetic with the classic cars of Cuba. Also, Havana has nice paint jobs on buildings and the cars alike. (Please Hexbear create a Havana theme), especially in a world where corporations are embracing minimalism en masse, and shit like 4chan is around telling the world "conform to inoffensive conservatism or else". It's nice to see some color happily shown. If there was a way to combine the two, I would nut.
Honestly just an efficient look for your actions. Stalin just wore a neat button up, Castro wore military garb, Lenin wore a suit. The look depends on what you are doing way more than some imagined aesthetic. We don't need aesthetics as much as the fascists because we have material substance, not a cool story.
Yeah, look neat, but not fancy.
Or look fancy, Robespierre and Jenny Marx had mad fashion game.