by chance

Just by chance I happened to find out a good deal.

He said they had met by chance at the party.

But who can know a woman's reason, or whether a thing is by chance alone, my father?

These three people who have nothing in common meet by chance.

By some chance I happened to have one with me.

Were we by any chance, the least in the world like one another?

If by any chance the street is full, he goes further.

She wanted to see if by any chance her son was coming.

If by any chance I don't see you for a year, you'll know something has happened to me.

We cannot leave this open for anyone to find by chance.