Right now, I only have a parking decal, university sticker, and a wildlife organization sticker in my back window. I've got a few more stickers (fishing gear, university, other organization stickers) that will likely end up on my window once the parking decal is gone. My newly acquired Glock sticker likely won't ever get put on it because I don't want to advertise too much. I don't really have any other clothing or stickers.
I'm glad you started this because I often wonder how much what I drive makes me more or less of a target. Does my F250 make potential bad guys think that I'm a harder target or does it matter? I know it's going to vary depending on the region. I would think a pro-gun sticker would be a partial deterent if you're with your car, but I think it would make it more of a target when alone. I think many people could look at my truck and stickers and infer a few things without me putting definitive labels on it. Is that a good thing or a bad thing? I don't know; I could be giving people more credit than they deserve.