Final Fantasy XIV added many new items along with the release of the Island Sanctuary in Patch 6.2 back in Aug. 2022. New clothing, hairstyles, bardings, minions, and more have all been added since then, but some of the most exciting additions have been the mounts.
Four mounts were added in 6.2, and three of them are veggie-inspired Mandragoras. Later on, three more were added, if you're interested in adding those to your collection. The Island Mandragora, Island Onion Prince, and Island Eggplant Knight are all available from Rank 1 at your Island Sanctuary.
These mounts can be picked up from the Horrendous Hoarder NPC in your hideaway (X: 12.6, Y: 28.3). They're purchased with Seafarer's Cowries, listed in the "Exclusive wares" menu under the "Others" tab. At 12,000 Seafarer's Cowries each, they're the cheapest mounts available from the Island Sanctuary, but that doesn't mean it'll necessarily be an easy sum to earn. Still, if you steadily increase your rank by doing various tasks around your island, it's very doable.
As you increase your Island Rank, you'll want to make sure that you're keeping up with your workshops, crops, and pasture to maximize Cowrie profit. Try to keep all of your workshops operational throughout the week, as the cowries you earn from exports will make up the bulk of your earnings. If you're interested in advancing on your island as quickly as possible, check out the Overseas Casuals Discord for workshop recommendations.
Once you've gathered up your 12,000 Seafarer's Cowries (or 36,000, if you're going for all of them), turn them in at your hideaway, and run off into the tropical sunset on the head of your veggie of choice.