New here and preferring to jump straight in. Hi.
I would say if I have any, mine are mild. I can't write with chalk and the sound of two pieces of stone against each other really bothers me, but they're not things I come across much in day to day life. The only other thing is that I find pressure calming, in that (for example) I can't sleep without a duvet over me. That's about it, I think. I actually love loud noise - loud music, the TV up high.
Meltdown-wise, I don't believe I've ever had a stereotypical meltdown. If I feel overloaded by a situation then I tend to shut down, sort of like a robot - I feel fuzzy-headed and like my consciousness has left me and tend to just sit or stand still and feel very calm more than anything else. Not sure if that's anything like a meltdown, or the complete opposite.