Here:
GameCube town 1- Marine Song 2001
GameCube Town 2- super Mario odyssey theme
Wild World- untitled learned on la di day
City Folk- unnamed made myself
New leaf- bubblegum kk
New horizons- somewhere over the rainbow
On my main island it's the little tune from Spirited Away, and on my secondary island it's the intro tune from Sims 3. Both were quick "I need a town tune for the Nook Miles Achievement" but both ended up staying. Neither is obnoxious when speaking to villagers and thankfully they don't feel repetitive when speaking to multiple villagers in a row.
I change my town tune quite a bit, but my current one in NH is the Tetris theme. My town tunes in NL and WW are Song of Storms and the Clock Town theme respectively, both from the Zelda series.
In New Leaf, I had Jinjo Village from Banjo-Tooie. Now, I have Spiral Mountain as my theme (from Banjo-Kazooie games as a whole). For a while I had Song of Storms (LOZ) but had to go back to my roots
NL: The beginning of the chorus to “No Big Deal” from Amphibia. I really wish my 3ds still worked.
NH: I’m not sure because my brother composed it and I haven’t played in forever, but it sounds like something out of a Super Mario game.