Outside of class abilities, there are many unique ways to improve mobility which allow even the least mobile of classes to traverse the open world more easily. Many of these may not work in other content in the game, or be less useful in said content.
Nitro Boosts - Belt enchantment, requires training Northrend Engineering. Massive speed boost, incredibly useful for pursuing escaping enemies, especially on classes with low mobility. Has a chance to explode on use, launching the player high into the air instead.
Being launched into the air can still be used for mobility, by using a glider kit (see Gliding section).
Rocket Boots - Require replacing the item in the Feet slot. Have niche uses.
Glider kits are consumables that allow any class to slow their fall and travel far horizontally while falling, with good air control and the ability to cast instant spells. Incredibly useful for pursuing escaping enemies, and are worth stocking up on for any world content. They last up to 2 minutes in the air, and can be cancelled early by right-clicking the buff with the item's name. Glider kits have a 3 minute shared cooldown and can be bought on the Auction House.
All Drakthyr and Demon Hunters have an in-built glide ability that is not as fast as a glider kit, but is still very useful for pursuing and canceling fall damage. Non-Evoker Drakthyr glide slower.
Silver Linin' Scepter - Toy that puts glider kits on cooldown/is put on cooldown by glider, only really useful as a backup.
Obtainable from a secret in Hallowfall. Chest appears after talking to each airship sky-captain around the Priory. (See WoWHead page for more information)
Gives slow fall, levitation, and water walking for 30 seconds, is only broken by attacking or casting yourself. Otherwise seems to work identically to the respective Mage, Priest, and Shaman abilities other than the animation. 5 minute cooldown.
Vulpera can uniquely use their Make Camp racial ability to set up a spot anywhere in the world to teleport back to.
Wormhole Generator are toys created with Engineering that allow for teleportation to any zone in a set area, which can be useful to quickly assist allies. They can be bought and sold on the Auction House, but require their expansion's Engineering profession to be learned to be used. They have long cooldowns, but can be very useful in many situations.
Wyrmhole Generator: Dragon Isles can be useful for quick travel to the Dragon Isles, which can be useful for PvP but is particularly helpful for hunting War Crates in the zone. Unlike most Wormholes, this one will only transport the player to a random part of the Isles unless they have specialised further into the expansion's Engineering profession, and so is not as useful for transportation to specific zones.
Wormholes will sometimes transport the player high into the air, which will lead to the player's death if they do not react quickly to prevent fall damage. If your class cannot prevent fall damage on their own, it may be useful to use a Goblin Glider or another item from the Gliding section.
Ancient Waygates also provide means to teleport within the Dragon Isles. They require level 7 renown with the Dragonscale Expedition to unlock initially with the Dormant Discovery quest, and then further renown levels with the Expedition to unlock more.
After teleporting, the player will have the Waygate Travel debuff for 30 minutes, stopping them from teleporting again. However, the player loses this if they die, so this can be done intentionally to traverse the Isles faster.