[Question] Where can I find more stones?

In preparation for the upcoming PCGF I've been searching high and low for magic stones. Somehow, I've managed to gather 93 stones, but now I think I've exhausted all of the most stamina-efficient/easiest places for gathering stones. I was wondering where I should focus on gathering stones. Here are some things I haven't done yet:

Challenge mode

• Starlight Sanctuary

• Legendary Seaway/Earth

• All of the 40 and 50 stamina technical dungeons

• Alt. Techs

Coin Dungeons

• Bowl/Dog Dragons

• 5x4 descends

• Tamadra Village (is a stone worth 10,000,000 coins?)

Anywhere I missed?