Here are two images of the joint issue - apart from the Luxembourg issue, all the others differ only in the name of the issuing country.

Luxembourg joint issue viewed from the angle which shows the Duke's head rather than the EU flag.

This is what all the non-Luxembourg joint commemoratives look like. I choose the Slovenian one at random - the others will differ only in the name of the issuing country and the mint mark, if appliable.
Hereunder are the country commemoratives of 2015, arranged alphabetically by country rather than chronologically.
Andorra

2015 - Granting of majority to 18 year olds.
Date of issue : 18.07.2016
Issuing Volume : 85,000

2015 - The second Andorran coin to be minted in 2015 but only issued in 2016.It commemorates the 25th anniversary of joining the EU customs union.
Date of issue : 18.07.2016
Issuing Volume : 85,000
Belgium

2015 - European Year of Development.
Date of issue : 15.09.2015
Issuing Volume : 250,000
Finland

2015 - 150 th Birthday of the great Finnish composer Sibelius.
Date of issue : 18.02.2015
Issuing Volume : 1 Million

2014 -
100th Birthday of Ilmari Tapiovaara.To the left of the Inner Ring are
the artists name plus birth and death dates. To the right is a furniture
segment typical of the artist.
Date of issue : 11.11.2014
Issuing Volume : 1 Million
France

2015 - 70 Years of Peace in Europe.
Date of issue :02.02.2015
Issuing Volume : 4,000,000

2015 - 225th Anniversary of the Founding of the Republic.
Date of issue :10.07.2015
Issuing Volume : 4,000,000
Germany

2015 - Pauls Church in Frankfurt am Main (Hessen).(The letter for the minting location appears between at 8 o'clock and 9 o'clock)
Date of issue : 30.01.2015
Issuing Volume : 30 Million

2015 - Commemorating 25 years of German unity.
Date of issue : 30.01.2015
Issuing Volume : 30 Million
Greece

2015 - 75th Anniversary of the death of Spyridon Louis.
Date of issue : 23.12.2015
Issuing Volume : 750.000
Italy

2015 - Universal Exposition - EXPO 2015 in Milan.
Date of issue : 27.04.2015
Issuing Volume : 3.5 Million

2015 - 750th Anniversary of the Dante's Birthday.
Date of issue : 26.06.2015
Issuing Volume : 3.5 Million
Latvia

2015 - Latvia's Presidency of the Council of the EU.
Planned Date of issue : 10.02.2015
Issuing Volume : 2,000,000

2015 - 10th Anniversary of the Black Stork Protection Programme.
Planned Date of issue : 01.12.2015
Issuing Volume : 1,010,000
Lithuania

2015 - The Lithuanian Language.
Date of issue : 12.12.2016
Issuing Volume : 1 Million
Luxembourg

2015 - 15th Anniversary of the Accession to the Throne of Grand Duke Henri.
Date of issue : 08.06.2015
Issuing Volume : 1,400,000

2015 - 125th Anniversary of the Dynasty Nassau-Weilburg.
Date of issue : 03.10.2015
Issuing Volume : 1,400.000
Malta

2015 - 100th Anniversary of the first Flight from Malta.
Date of issue : 25.05.2015
Issuing Volume : 300.000

2015 - Establishment of the Republic of Malta in 1974.
Date of issue : 05.10.2015
Issuing Volume : 400.000
Monaco

2015 - 800 years since the building of the Fortress on the rock of Monaco.
Date of issue : 09.11.2015
Issuing Volume : 10.000
Portugal

2015 - 150th Anniversary of the founding of the Portugese Red Cross.
Date of issue : 15.04.2015
Issuing Volume : 520.000

2015 - 500th Anniversary of Portugese landing in Timor.
Date of issue : 15.07.2015
Issuing Volume : 520.000
San Marino

2015 - 750th anniversary of the birth of Dante Alighieri.
Date of issue : 08.04.2015
Issuing Volume : 104.000

2015 - 25th anniversary of German unification.
Date of issue : 15.09.2015
Issuing Volume : 250.000
Slovakia

2015 - 200 Anniversary of the birthday of Ludovit Stur.
Date of issue : 23.10.2015
Issuing Volume : 1 Million
Slovenia

2015 - The 2000th Anniversary of the founding of Emona.
Date of issue : January 2015.
Issuing Volume : 1 Million
Spain

2015 - Cave of Altamira and Paleolithic Cave Art of Northern Spain.
Date of issue : February/March 2015
Issuing Volume : 8 Million
Vatican

2015 - VIII World Meeting of Families in Philadelphia.
Date of issue : 06.10.2015
Issuing Volume : 122.000
Return from Euro Coin News 2015 to euro coin collector.