Shōnen rival? But seriously, I'll be honest, I've only seen male characters like that (competitive, hostile, mean, but have moments where they display other emotions, gradually warm up to their rival and in the end they become friends). I'm pretty sure that even if it's friendship, not romance, it counts as tsundere. I don't even know why I made that distinction, it was dumb, sorry.
B-but I don't want to derail the thread, I believe you guys were talking about cute tsundere girls. They're almost always either "modern" (the most popular currently, usually portrayed as borderline bipolar and kinda shit tbh) or "classic" (which I guess is similar to what I described before). I don't think the personality of a modern tsundere would be tolerable in real life.