Ground-type Rhyhorn and its evolutions, Rhydon and Rhyperior, are obtainable in Pokemon Scarlet & Violet as of the 3.0.0 update and release of the Indigo Disk, part 2 of the expansion pass. If you plan on catching Rhyhorn or Rhydon in the wild, you will need the expansion pass to gain access to Terarium of Blueberry Academy. Getting the Rhyhorn-line's final evolution, Rhyperior, will take some more work.
Pokemon Scarlet & Violet: How to Get Rhyhorn, Rhydon, and Rhyperior (Indigo Disk)
You'll need to catch Rhyhorn and its evolutions to fill out the pages of the Blueberry Pokedex in Pokemon Scarlet & Violet's Indigo Disk DLC.
