I was bored, so I looked for backing vocalists and composers of ESC entries from the latest years and that is what I found out.
You may not know everyone, but the majority of course.
Usually I got really in shock when I read 'person abc' was backing vocalist/composer of 'entry xyz'.
Netherlands 1996,
Belgium 2002,
Netherlands 2009: Backing vocal: Ingrid Simons (Mother of 'Eva Simons')
Croatia 2003,
Slovenia 2007,
Montenegro 2008,
Slovenia 2011,
Slovenia 2012: Backing vocals: Martina Majerle (
Slovenia 2009)
Iceland 2003: Backing vocals: Regina Osk (
Iceland 2008,
Icelandic NF 2012)
Macedonia 2004: Backing vocals: Tamara Todevska (
Macedonia 2008)
Iceland 2005: Regina Osk (see above ^^)
Lithuania 2005: Backing vocals: Sonja Aldén (
Melodifestivalen participant 2006, 2007, 2012)
France 2006: Composer: Corneille (
French singer, know him from MMC
)
Ireland 2006: Backing vocals: Una Healy (member of 'The Saturdays')
Lithuania 2006: Member of 'LT United': Marijonas Mikutavičius (know his song "Celebrate Basketball")
Macedonia 2006: Backing vocals: Aleksandra Pileva (
Macedonian NF 2005)
Switzerland 2006: Member of 'six4one': Andreas Lundstedt (member of 'Alcazar'; several
Melodifestivalen appearances)
Serbia 2007: Backing vocals: Ana Milenković (know her song "Nevidljiva", has also participated in TVSC)
Georgia 2008: Backing vocals: Anri Jokhadze (
Georgia 2012)
Latvia 2008: Backing vocals: Liene Candy (
Latvian NF 2013)
Hungary 2009: Backing vocals: Heincz Gábor (
Hungarian NF 2012)
Iceland 2009: Backing vocals: Erna Hrönn Ólafsdóttir (
Icelandic NF 2013), Hera Björk (
Danish NF 2009,
Iceland 2010) & Friðrik Ómar Hjörleifsson (
Iceland 2008)
Turkey 2009: Composer: Sinan Akcil (know his song "Atma" for example)
Armenia 2010: Backing vocals: Gor Sujyan (
Armenia 2013)
Germany 2010 & 2011: Backing vocals: Maya Saban (know her because she's german
e.g. her songs "Das alles ändert nichts daran" or "Aus und vorbei")
Iceland 2010: Backing vocals: Erna Hrönn Ólafsdóttir (see above ^^)
Ireland 2010: Backing vocals: Nikki Kavanagh (
Irish NF 2011)
Albania 2011: Backing vocals: Bledar Sejko (
Albania 2013)
Belarus 2011: Backing vocals: Uzari (
Belarusian NF 2012 & 2013)
Lithuania 2012: Composer: Brandon Stone (he's a
German-Georgian singer; participated in MMC; participated in The Voice of Germany)
Malta 2012: Backing vocals (sung "This is the night, This is the niiiiight"): Amber (
several appearances in the Maltese NF)
Moldova 2012: Backing vocals: Aliona Moon (
Moldova 2013)