Each Pokémon has their own individual model, but most of the animations for those models are shared among similar body types. Which animation comes from where is defined in the BGRS file corresponding to the model, but unfortunately, there's no UI for that right now. However, there is a UI for another file that can help: /BaseRom/Raw Files/RomFS/pokemon_graphics_database.bin. Open that in Sky Editor using File -> Open, and type in the name of the BGRS:
In this example, the generic body type is "float_body_00", so if you look in that folder in the model project, you'll see a bunch of generic animations:
These can be imported into your choice of modeling program such as SPICA or Ohana.
Each of the generic animation sets contains an animation for sleeping in a dungeon. The starter mod will independently copy those over to apply to the overworld.