I usually ride around on my spider buggy but decided to swap to my ant buggy to harvest some grass and move it. It said all of my buggies were marked “Not Available.” I went back to the nest to give it a try and it would not withdraw the buggy. I restarted my game and had the same problem. Then I had the brilliant idea to send my spider to the nest because maybe that was the reason it would not let me withdraw my ant. Sent the spider away. Now I can’t withdraw it either. They all show up in the nest. I’ve cleared and reassigned the summon spots. No dice. I died and respawned at the outpost. Still nothing. Game repair did not work. Any ideas?

This sounds like Grounded 2 — the buggies going "downed" and returning to their nest to auto-revive matches what you're describing, so the "Not Available" status might just mean they're mid-revive rather than actually stuck. That said, buggies not coming back out even after you've cleared/reassigned summon spots and reloaded sounds like it's crossed into genuine save-corruption territory, so I'd report it directly on the Grounded 2 official Discord or Obsidian's bug tracker with your save file — this kind of persistent state bug across a restart usually needs a dev-side fix, not a player workaround.