I have had small coincidences happen, not big ones like running into long lost relatives or anything, but fun nevertheless.
Back in the 80s, I used to buy household things from a catalog, and the company gave free gifts with each order. So one of the free gifts was a set of four soup cups. I kept them for years, until two of them got shattered, I was down to two. I figured I only needed two, but then while unpacking dishes, another was broken. I was bummed. And then on top of that, the lid to a set of canisters got broken as well. So now I had one soup cup left, and a canister with no lid. The company that made these dishes probably didn't even exist anymore.
We went into a thrift shop to look around and as we were inspecting the dishes, not only did we find a canister with the lid I needed, I also found another of those soup cups! Now I have two cups again, and a replacement lid for canister!