Thank you for your replies.
Kittykat200, my idea was to have everything in black, apart from the background of triangles (which will be pink and black) and the rainbow. I want it to have colour in it, I don’t want the whole sleeve to be black, but at the same time, not so much that it clashes. I want it to stand out on my arm somewhat though.

A possibility I had in mind was to have the background of triangles outlined in black, and only some of them coloured in. This really is only in the planning process right now, as you’ve probably guessed.

Do you think the rainbow is too much in there too then? Also, do you think text can work in a sleeve, I’ve heard that it can look quite strange, and it’s quite an unusual thing to do; but I’ve never seen firsthand. I just don’t want to incorporate it if it’s going to look out of place.

My essential things to have in there are the (black) feminist fist and the pink and black triangles – I’ve had those in mind for a long time.

Thank you again for your advice.