At least the following places are on my short list:
The map of Europe and I placed the HD flag in all countries I visited with one of my Harley bikes.
So I still have a couple of countries left on my bucket list.
Recent, August 2015, I visit Roemenia, via Austria and Hungari. The ride back home was via Servia, Croatie, Slovenia and Italia. In the European chart I did not complete fill in Roemenia, because I visit only the west side of the country.
In 2016 I added Liechtenstein to this chart. And in 2017 Ireland (both North and South are added)
For 2018 Scotland was added and in 2019 I added Andorra and the south part of Italy.
Update for 2019: A visit to Andorra, with the boys to Isle of Man and with my daughter to the Baltic States and Russia.
Update for 2023: For the Ride2Eat in Athene also a visit to other Balkan countries.
On top of this list, I also visited with one of my bikes the small city-states: Vaticaan city, Liechtenstein, San Marino and Andorra.
The map below is Europe with all places I visit. So all others had be in the DiscoverMore2015 ride.
So because I wasn't choosen for the ride, I will plan in the coming years my route to visit all these countries.