Any DJ worth their salt will have:
Palo Pa' Rumba by Eddie Palmieri
Pablo Pueblo and also Juan Pachanga by Rubén Blades
Quitate La Máscara by Ray Barretto
La Banda by Hector Lavoe
Mama Guela (dozens of good versions! Fania All Stars did a classic, so did Spanish Harlem Orchestra)
Coro Miyare by Fania All Stars
Yamulemau by Joe Arroyo
Mi Cucu by La Sonora Dinamita
La Piragua by Gabriel Romero
Fruta Fresca by Carlos Vives is also popular, but not really salsa or cumbia.
Cumbia de los Muertos by Ozomatli is very popular in certain circles, not sure if it's what you're after or not.
Edit: I forgot to mention: Quimbara, another song with quite a few versions. Most likely you will have heard the Celia Cruz version.
