Examples that come to mind:
- saying your favorite video game is Disco Elysium
- saying your favorite TV show is Star Trek DS9
The two rules are that:
- It has to be to do with a category that is socially acceptable to talk about with most people in a casual setting. So no politics or philosophy.
- Nothing too on the nose, ex, no "I love the music of the Red Army Choir" or something.
back when I gave a fuck I put a "I fucking warned you dude, I told you bro" Capital book cover meme in my profile. Got me one good date lol but not exactly subtle
Now I either tell people straight up or I don't, I guess some people might catch on by the way I speak about some topics but I'm pretty reserved in public
as for a real answer: your options are basically memes/subculture stuff as you've mentioned, coy references or talking about the actual work you are doing in organizing or mutual aid without making explicitly "political" statements about it.