I think it should be acknowledge that Namor is explicitly described as “erotic” in the 60′s Marvel Superhero song
Well I always think Namor likes a lot of Atlantean music, which to me is kinda like a mix between haunting Siren type songs like; Siren Song, or Cave of the Mermen, or Song of the Sirens, and songs by The Hu. So to me Atlantean songs are really just haunting and filled with their culture, songs of the sea, and of its history.
The kind of human songs Namor would listen to most imo is songs that were around in the 1940s or have feel of older music like; Sing Sing Sing, Why don’t you do right?, since that was his first real interaction with humans. Of course he probably listened to a lot of sea shanties from passing ships who liked to keep up that tradition at sea, but also songs that were popular during the war probably; Bulge Boy, etc.
As for modern day songs, I usually use these songs to get in the Modern Namor writing headspace since I feel it fits his; less innocent of the cruelty of the world of man / heartbroken tired old king personality so lots of “f*ck you!” and “I’m very alone and very sad” songs:
Hope this answer helps!