I found my phone in the freezer once. I think what happened is I went to get something out of the freezer and a bunch of things tried to fall out. So I set it down in the shelf for a sec to stuff things back in and forgot about it.
I spent hours trying to find it until I went back to the freezer for something else and there it was.
Then there was the time that I had a phone in the innner pocket, forgot it was there and washed it, but that's another story
Best of luck in finding it. Common places for me are seat/couch cushions, car (I thought I brought it in but didn't), under mail/papers that I set on top of it.