here are a few for songs by a few bands:
Genesis: Return of the Giant Hogweed, The Fountain of Salmacis, Dancing With the Moonlit Knight, Watcher of the Skies, Cinema Show, Supper's Ready
Emerson, Lake and Palmer: Karn Evil 9, Tarkus
King Crimson: Starless, 21st Century Schizoid Man, Epitath
Yes (even though your example is already by them, just in case you don't know all of these): Heart of the Sunrise (my personal favourite of all these), Starship Trooper, And You And I, The Revealing Science of God, I've Seen All Good People, The Gates of Delirium
and, despite how different they are from the rest, The Mars Volta are very much prog and I can't not recommend them: Cygnus....Vismund Cygnus, Take the Veil Cerpin Tazt, Cassandra Gemini