Almost all the various times we get to teleport, the mechanism and graphics are different. It is hard to pin them down to have one originator.
Just in Prophesies, there are quite a few. I might have missed some.
The multiple golden doors in Surmia that takes you to Nolani Academy.
The crystal/Druid activated teleporters in Maguuma Jungle.
The different coloured swirly portals in Dragon's Lair.
And as mentioned, the portal that took us from Thunderhead Keep to Ember Light Camp. It has a structural gate made of stone?
Also, swirly portals in Lion's Gate related to the Nightfall quests.