If you're in Elixir-land, I've put together a few packages to help migrating from Supabase (or other stacks):

- https://github.com/agoodway/introspex (generate Ecto Schemas from postgres tables)

- https://github.com/agoodway/pgrest (Supabase/PostgREST compatible query engine)

I also found this helpful in the migration: https://github.com/supabase-community/supabase-ex

Nothing for auth, I basically did a one-off script for that. Phoenix auth stuff that comes out of the box is great.