This topic led to a very diverse selection of songs. A variety of genres and decades are represented throughout my picks. There's something to enjoy for everyone 
Childish Gambino - II. Shadows
https://youtu.be/VRfJOrUxWWI?si=G5PrIoHtYZibp3ff
Destroy Boys - Shadow (I'm Breaking Down)
https://youtu.be/Uf5adSoFPc4?si=gqnnDYnE2yG3JZ-i
Wolfsheim - Everyone Who Casts A Shadow
https://youtu.be/tW_D0AlTfLI?si=Vh5bfc4RZRtq5KMw
Groove Coverage - Moonlight Shadow
https://youtu.be/5gHGIY1Q-yU?si=hCZ8fzEDZuRfZ7fO
Two Of Us - Blue Night Shadow
https://youtu.be/PBQA1Veystk?si=1uTVpkNlY3q8lXr7
I also made a (mostly) german list with some great songs. One of the titles isn't referring to shadows, but it's mentioned in the song itself... a lot!?
Parkway Drive & Casper - Schattenboxen
https://youtu.be/uwm0nvlZwgk?si=8YKcVfE4tIBgLgx3
Lacrimosa - Lichtgestalt
https://youtu.be/vDBK8yN2lrU?si=u7Xhwsh0mb8YxsiU
Tocotronic - Schatten werfen keine Schatten
https://youtu.be/yJwLEFZ2o-M?si=2XvfSqB7Ud3MxqZH
Rantanplan - Schattenmensch
https://youtu.be/eIyxR-zGDsk?si=_rq_B2AiAtiH13Bu
Saltatio Mortis - Licht und Schatten
https://youtu.be/_f0mOZkB2LE?si=0tVn2SMb2e0ndSy5