Olympiacos are technically from Piraeus, which is in the club name. Although, Piraeus is a part of the Athens metro area so I suppose it comes down to where you draw the line.
I like the idea of the quiz! Wide selection of teams, some of them very obscure for a casual Jetpunker not-so-much into Football like myself. I would suggest you divide them by country/league though, and to make it clear that we are in UEFA countries not another continent. I was trying a lot of Brazilian cities for Olympiacos!
Other than that a good selection of teams!
Benfica
Young Boys