Yagluth and queen are notably the worst to find, the locating stunes are scant but both summoning areas aren't hard to miss. All the others have many more chances for locating stones to spawn

Elder has burial mounds and above ground towers, bonemass in crypts and above ground towers, Moder in ice caves and above ground towers.

Yagluth sometimes appear in rare to find hedge stone like areas, yep that's it. As far as I've experienced queen is only sometimes in those seeker pits in the infested mines

his marker is inside a crypt

some bonemass markers are found in the ruined towers in the swamp too. If you don't like looking for Bonemass your going to love Yagluth.

His marker is inside a lot of crypts but you have to play the game to find them. This is not that game you run through with your pants on fire (usually, wink wink) so you can finish it really fast then complain about no content.

Originally posted by Frank Dunn:

some bonemass markers are found in the ruined towers in the swamp too. If you don't like looking for Bonemass your going to love Yagluth.

At least Yagluth's altar is obvious and visible from a distance, I've stumbled across them while sailing more than I've located via Vegvisir.

Good luck with Moder too. Sometimes it's not bad, but I've seen maps where they're all on the edge surrounded by Mistlands.

I find Moder isn't too bad so long as you judge that a mountain is high enough to potentially have a Vegvisir or her altar. My first playthrough I had trouble because by chance all my islands I explored only had low level mountains with the snow but not the Draugr forts. And that was before Ice Caverns were added.

Now I sail until I find a truly tall shape looming in the distance and scaling those peaks I can at least find a Vegvisir, either in a fort or a cave.