Today 10 years ago I went to Poland to buy a Phone with pre installed #Firefox OS on. The Phone was a Alcatel One, so very shitty. Two years later I installed Firefox OS on my Nexus 5 instead.
It was a very good concept, but sadly rolled out on too shitty hardware so it never caught on.
I once had the Nokia N9 with MeeGo on it.
https://www.wikipedia.org/wiki/Nokia_N9
It was a great phone, but sadly there was little support for (3rd party) apps. I had it for like 3 months, could still get a buck for it (wish I’d kept it) and bought something else with the money.