I know this may be out of topic, but several singers had participated in Juara Lagu with the less popular songs:
Hasnol: Sudi Katakan Sudi, that song is less popular, compared to Laguku Untukmu which became a popular hit after a contestant sang it on a reality show.
Awie: 1995 with Di Bayang Awan. Tragedi Oktober is more popular. However for me, I heard that song through the cassette in the car when I was ready to go to school (2005).
Man Bai: The singer for Gersang had participated with two songs in Juara Lagu (1988), and another one in the next year. He returned in 1996 with "Sebenarnya", which we heard less often than "Kau Ilhamku".
Adilla: Also participated in Juara Lagu 1996 (second time, after 1994, who replaces Iklim who had changed their record company) with "Janji Seorang Kekasih". But people hardly find this song on radio stations.
M. Nasir: Andalusia is less popular than Kias Fansuri.
Syafinaz: Impian Realiti is forgettable, while Ingin Bersamamu, which is also the name of the album is popular than the former.
Exists: Jesnita is more popular, when compared to Julia. And the former also won an award in Anugerah Era 2002 for Anugerah Carta Era award.
I cannot remember the others, but I believe there is some more.
1 MALAYSIA, Rakyat Didahulukan, Pencapaian Diutamakan