In the city of Liyue, there is a Luxurious chest that's on the roof of a building near the very end of the east area where the ships are.
Ship East of Liyue Harbor
There is also a Luxurious chest on the ship that's close to the city. You might have to glide there from the cliff down south, but if you've already cleared the related quest inside the ship, you can return there by talking to Pinghai the boatman near the boats.
Side Quest - Treasure Lost, Treasure Found
This area is related to the quest "Treasure Lost, Treasure Found Quest." Complete the quest and you will unlock the seal in the center and be able to claim a luxurious.
Guyun Stone Forest is southeast of Liyue Region. You can teleport to the domain area if you've already unlocked it, then go west of it to the other small island, and you will find 4 ruin guards there. You will have to clear them all to reveal the Luxurious.
You will need another player for this one. North of Guyun Stone Forest area, where the Geo Hypostasis is, there is an island with a heart on it. You can reach there by going just north of the Geo Hypostasis and use an Anemo skill on the small windmill to create an upcurrent, then glide to the island. Stand on the heart and a Luxurious chest will appear. If it doesn't appear, then you might need different genders of the characters, or relog the game.
Southeast of Guyun Stone Forest, there is a pirate ship that you can reach by climbing up the mountain of the domain area. The Luxurious chest is at the top of the lookout area.
North of Liyue Harbor Mountain
North of Liyue Harbor, there is a very tall mountain that you can climb. At the top of it, you will have to light the fire candle to create an upcurrent. Then fly up and drop down to the small pillar near it to find a Luxurious.
Side Quest - Chi of Guyun
This area is related to the "Chi of Guyun" quest, though you can easily miss this one. Near the top of the mountain in Wuwang Hill, you will find some lion statues. There is a Luxurious chest just in front of the one facing near a tree.
There are several Luxurious on the top of the Qingyun Peak area, on the floating rock in the air. You will have to go to the surrounding mountains and find the stone bird statues, and turn them to face the mountain. Once all 3 are facing there, a wind upcurrent will show up so that you can fly up there.
Side Quest - Luhua Landscape
North of Liyue Harbor. This area is related to "Luhua Landscape" side quest. Complete the quest, and the entrance to the ruins will open.