Battle on the Dragon Isles II

With 10.0.7 there are 8 total new pet battle world quests in the initial 4 Dragonflight zones, 2 in each zone.

They've also upped it so that there's 1 pet battle world quest per zone per day (5 per day including the Forbidden Reach which is not needed for this achievement), so with favourable RNG this achievement could be done in as few as 2 days. Each zone has a "boss battle" WQ with just the one very powerful enemy and a "trainer" WQ with a team of less powerful pets.

Waking Shores
Adinakon asks you to fight boss battle Adinakon.
Sharp as Flint has you battling Excavator Morgrum Emberflint with the three pets Enchanted Tuskling, Lord Flappinsby and Feral Frogduck.

Ohn'ahran Plains
Lyver asks you to fight boss battle Lyver.
Paws of Thunder has you battling Vikshi Thunderpaw with the three pets Arctichnid, Drakeula and Yu'shor.

Azure Span
Enok the Stinky asks you to fight boss battle Enok the Stinky.
A New Vocation has you battling Izal Whitemoon with the three pets Blu'jaeden, Mothoroth and Kazzquack.

Thaldraszus
Right Twice a Day asks you to fight boss battle Malfunctioning Matrix.
They're Full of Stars! has you battling Stargazer Zenoth with the three pets Celastro, Cozmos and Lil' Algalon.

/way #2022 51.89 72.36 Adinakon
/way #2022 69.01 46.73 Sharp as Flint
/way #2023 73.42 67.99 Lyver
/way #2023 36.13 52.57 Paws of Thunder
/way #2024 23.41 53.54 Enok the Stinky
/way #2024 19.52 24.60 A New Vocation
/way #2025 60.69 59.71 Right Twice a Day
/way #2025 55.97 40.54 They're Full of Stars

There are great comments by DragonsAfterDark on each of those pages with strats for defeating each trainer/boss so be sure to check them out if you need help.

Apparently you only get credit defeating them if the world quest is up.

Blizzard has found a new way to annoy, I'd bet that they expand that in the future.

even more annoyingly - the WQ didnt credit towards the acheivement