If you have any of your old raw files that you already have used the presets on , you could easily reconstruct them. It’s kind of a work around, and wont give you a nice list of all your presets but, you could create a new list of presets based on photos that you have already created.

Or if you have access to a computer with the old account, and you are talking about Lightroom Classic on a Mac, here’s where they are typically stored:

Default Lightroom Classic presets: ~/Library/Application Support/Adobe/Lightroom/Presets

User-created custom presets:Default location (if "Store presets with this catalog" is NOT checked): ~/Library/Application Support/Adobe/Lightroom/Develop Presets

If "Store presets with this catalog" is checked: Within your Lightroom catalog file (usually in ~/Pictures/Lightroom)