Dungeon Keys

So I have a problem with locating certain dungeon keys. I know that you get them from key guardians but the problem lies in finding them. Decrepit sewers, infested pit and underground crypt keys and easy but i can't seem to find any sand-swept tomb or lost sanctuary key guardians anywhere at all.

Are there any locations where they are more common? If so could someone please tell me.

Thanks in advance.

 

SST: By the river in almuj, apparently relatively common near where soft sand spawns.
Lost sanctuary: seen one near time valley, you would see it around mt. wynn aswell iirc

for future references:
GG guardians spawn in these spots:
- Fountain of Youth (dernel)
- Swamp (near kander transition to be specific)

UR:
- Fountain of Youth (dernel)
unsure if other spots exist

also to note for the corrupted dungeon keys just get them from market, it's usually a block or two

 

Thank you so much! After going to the mentioned locations I finally have the keys. Thanks once again.