'Save Current Settings as New Preset...' would allow you to rebuild those options.
These drop down box choices are called Filter Presets and the default presets don't include any that display 2 star images or whatever - you just get choices for Rated or Unrated. But if you could previously choose 2 stars, that means you would have saved presets of your own. They are actually saved as text files in a hidden system folder such as C:\Users\USER\AppData\Roaming\Adobe\Lightroom\Filter Presets (Preferences > Presets > Show LR Presets Folder), but alternatively you can use Store Presets with this Catalog (Prefs > Presets) to keep them in the same folder as your catalogue. So look for that folder in the same folder as your catalogue.