One in a gazillion!!
Here is one, I may have posted it here on the site. Years ago I was flying to Florida and on the flight I took the book The Scientist by John C Lilly. I had takes some notes from another web sight that existed and this was 1997 so not many existed. The term dolphinicity was rolling around in my head, a synchronicity involving dolphins which were many. The book was also talking of dolphin coincidences. So the plane has not taken off yet. I am sitting there thinking about dolphinicities and at that moment the TV screen above my head lit up. It had switched from off to on for just a moment. A blue dot was in the middle of the screen. It got bigger and bigger and then from the center a dolphin face jumps out of the ocean and winks at me from the screen and then just after that the TV went off until we were in the air. Not sure what that was, a commercial, an ad, it was just a moment on the screen. Not sure but it had a big impact on me as far as coincidences.
Given the infinite nature of things, the "chances" things could fall into line is plausable. Then there are some coincidences that make us take note and seem a little more than just a coincidence.