I can't confirm if these are all the locations, but I have found 29 locations in 19 different tiles
So far, I've done 25 consecutive missions without a new location

• Naeglar, Eris

My cache guides:
Ceres, Corpus ship, Deimos, Earth, Grineer ship, Hive, Jupiter, Kuva Fortress, Lua, Uranus, Void

Tile 1


Tile 2
1
2


Tile 3
1
2
3


Tile 4


Tile 5
1
2

Tile 6
Jump to the top level


Tile 7
An explosive barrel opens up this wall


Tile 8
1
Up a ledge
2


Tile 9
You can see the cache through the window. Shoot the explosive barrel the my waypoint


Tile 10
An explosive barrel opens up this wall


Tile 11
Through the hole in the ceiling


Tile 12


Tile 13
1
2
3
4
I forgot to take screenshot when I got a cache here
5
This is the lower level of the room


Tile 14


Tile 15

Tile 16
1
2
Through the vent in the wall in the top left

Tile 17

Tile 18
1
2


Tile 19
An explosive barrel opens up this wall

Some secretive places I've come across

1
Another bigger room

2
Another extraction room

3
Tile 6

4
Tile 8

5
Tile 8

20 / 10 / 2022
Added locations:
Tile 8 2
Tile 13 3 (currently recounting consecutive runs)

3 / 11 / 2024
Increased run count: now 25 runs without a new cache spawn

I hope these screenshots are easy enough to follow. I find that they're not as clear as in my other guides.