Fiorwoods loop might be worth adding, since no fights.
Sandstorm oasis above new wynshire has 3, and you can go down into the dark cave from there for 2 more ( can also get to cave from east ogane tp, which also has 1 or 2 along the path down to the cave)

In the Flower Fields, in the very top middle by the cave entrance, that little side pouch to the south west has one crystal.

Crystals seem to be on a 30 minute timer.

Also another great spot is the Isle of Messages. This spot is just south of Shambala around a couple of rocks jutting out from the sea on the edge of the continent. Clearly a place for backers to leave messages ingame, but there are a total of 11 crystals there.

Thanks!

@syrin Yes, but I'm unsure as to the trigger. I think it is time passed.

Do crystals respawn?

Maybe add Leviathan Trench? The southern Route has 6 spots combined
and at lv20+ its easy to kill mobs

3 crystals in Fiorwoods North East, wooden walkways
3 crystals in Fiorwoods East, wooden walkways
2 crystals in Fiorwoods South East, 1 top right, 1 bottom

2 crystals in Perpetua North West, near the other crystal already noted (one next to it, one a little south of it)
1 crystal in Perpetua North, top of the area near northern exit

3 crystals in South West Kortara, closely packed together in the Wyggrand Mines
1 in South East Kortara, center left, north of the western exit
2 close together in the mines in south Rockbottom (East Kortara)

In the mines is a bit out of the way for quick travel, so I haven't bothered