As requested by one of my readers, here's a list of the locations of a few of the rare Miscrits in the game.
Mun Kee is at the peak of Mount Gemma, in the crystal rocks at the edge past the Earth Elementum. The Earth Elementum must be defeated before you can reach it. You can find it there Tuesday through Friday. You can read my review of Mun Kee here: Mun Kee Review
Thundercracker is in the second section of Mount Gemma, in the cactus on the edge of the cliff. Just walk west and a little north after you cross the Eternal Falls. It's there Saturday, Sunday, and Monday.
Treemur is in dead looking trees in the forest on Mondays and Thursdays (such as the brown trees with no leaves).
Blazebit is always available inside the Elder Tree and the two bushes on either side of it.
Remember, they are all rares so it will probably take several tries to find them. You can always check with the Explorers at the entrances of Mount Gemma and the Miscrian Forest to find out some information about the rares available for the day.