The very first Indian restaurant I ever went to back in the 90s, had chutneys sitting at the table. Two were the usual ones, which I still see all the time: Mint and Tamarind. But they had a third one I've never seen anywhere else.

AFTER ALMOST THIRTY YEARS I FOUND IT! It's not a tomato chutney like I thought it was, which is why I could never find it. It's an ONION Chutney. I may hit an indian grocery grab some poppadum (they look awesome when you cook them in the microwave), and make some of this for old time's sake: https://www.jcookingodyssey.com/indian-onion-chutney-recipe/