In addition to the Hearthstone and any toys that grant teleportation to specific places, there are also items that we need to keep in our bags that teleport again to specific zones (rings that teleport to Boralus/Dalaran/Kharazan, trinkets to Timeless Isle, a a bunch of others).
Currently, it’s getting too cluttered to keep all of these, and even remember all the teleportation options.
So, the sugegstions is to create a separate teleportation menu (like we have for mounts, pets, toys, appearences), where all possible teleportation spells/options will be kept. And the unlock for any of them would remain the same (i.e. if I bought a ring that teleports me to Dalaran in Northrend, the spell to teleport to this Dalaran would become unlocked for me, and I don’t have to keep the ring in my bag anymore).
I suppose it would take a small effort in the beginning to track all items that have teleportation on them, but that are aggregated lists of these on WoWHead already.
This page could also store any other teleport spells (like mage teleports, our hearthstone, any toys, items, any consumable teleports that could be charged, etc…)