Map of Europe, showing GDP by metropolitan region.
Dark red circles: Metropolitan areas with GDP of more than 50 billion EUR (short scale)
Bright red circles: Metropolitan area with GDP between 25 and 50 billion EUR
Orange circles: Metropolitan areas with GDO between 10 and 25 billion EUR
Green circles: Sum of all non-metropolitan areas of a country and the metropolitan areas of below-10 billion GDP.
In ocre, EU member states and in grey, non-member states.
Metropolitan data for all EU member states, plus Switzerland and Norway. No metropolitan data (so the green circle matches the national GDP) for UK, Turkey, Serbia, Bosnia, North Macedonia, Kosovo and Montenegro. No data for Moldova, Ukraine and non-European countries.

Source: EuroStat met-10r-3gdp dataset for 2018 combined with b1gq dataset, showing CP_MEUR for 2018, inflation adjusted for 04/2022 ("current market prices").
Own work / data from EuroStat as per description
Enyavar