Maintenance for the week of October 5:
• [COMPLETE] ESO Store and Account System for maintenance – October 8, 8:00AM EDT (12:00 UTC) – 12:00PM EDT (16:00 UTC)
If a player deletes a character that has purchased mounts from the store, are these bound to the character or the account? Will the mounts be lost if the character that purchased them gets deleted?
The mounts are tied to your account, on the server where they were purchased. This is true for Crown mounts but also the four horses purchasable with gold. It is also true for all costumes and pets, even the quest reward ones.
So if you delete the character, you keep the mount.
If you decide to play on a different server (from NA to EU or the inverse), you would need to reobtain the mount, but it will still be available on your original server where it was purchased.