While there are other breed of wyverns in existence, these specific wyverns, referred to as tier 1 and 2 wyverns, only appear in a dimension known as The Wyvern Lair. They all possess both a venomous sting and bite and are actively carnivorous and aggressive. The only way to tame one is to raise it from birth.
There are tales of an undead mother wyvern being used as a mount for a now dead necromancer, but no one’s been able to get their hands on a mother wyvern to confirm if this is possible.
(Well, there are two, but neither are cruel enough or loyal enough to a ruler to try)