I am a slow movement enthusiast. Here are just a few of my favorites (all
slow movements and not in rank order):

Dvorak: "American" Quartet
Schubert: C Major Quintet
Schubert: Symphony No. 9
Beethoven: Symphony No. 3
Beethoven: "Emperor" Piano Concerto
Mozart: G minor Quintet
Dvorak: Cello Concerto
Strauss: "Abendrot" from 4 Last Songs (does that count as a "movement?")
Rachmaninoff: Symphonic Dances, 1st movement

Chris Bonds