I can not, for the life of me, find these symbols. I've gone around this entire map it seems, but still can not find any past the first. Welp, took a bit but finally found them. I think it was Rune Epsilon, but it wasn't all that close to the edge of the map and was surrounded in grass, but finally accidently just barely hit the sound radius for it while running around, below it nonetheless.
Also, what is that one mon in the gallery at the top right? Also can not find it anywhere.
Also, very goofy choice for the 'Haunting Creature' but also cool.