The information you requested was no easy task to uncover for the venerable church, but my dedication as a mume-kin proved most worthy this past season. Most of this knowledge was discovered from the Elder-Library of South Briston, a hidden Felf community that has dedicated themselves toward the collection of data. If ever you are released by the church of the Living Goddess, I highly recommend finding this library. It is awe inspiring.
You're guesses of 6 artifacts was almost correct. There are seven and not six. Manipulation of reality, or Magic as you stubbornly call it, comes in more varieties than you may think and more than the great races have respective artifacts, minus the two new races of Mume kin and Rabbit Kin. The collection of these artifacts is called by the Felk Kin "The Remarkable Treasures."
The Scepter of Ouroboros, who's magic is unknowable, is held jealously by the Ixxar. It is as secret as the Ixxar are themselves of their magic. I highly recommend you avoid this treasure for fear of the entire race coming down on Annalow, which would be disastrous.
The Andross Mechanism, a clock-like construction of ancient felf design seems to grant fox-like gifts. It's where abouts is unknown, but it's power was once used at the Shrinking Mountains.
The Grock-Min-Sol (translated from Old-Borc: "The Blade of the High Sun" or "Noon Sun.") History has seen this sword recently. Heaven forbid it shows again, because its last master was Fargo Ipskin, may his name forever be spit on.
The Rod of Four Things you already know about. I believe it was a gift from the Marf to the Church through the immortal Red Maid Carr'Dine. It grants the Marf's gift of manipulating physical substance.
The Apple of Peace was not of the Great Races, but your guess was correct as to it's location. Those who have touched it know unending certainty and calm. I don't know how this works as it is Crow-Kin magic. It was buried in the eastern lands with Quiet King Merch of the Marf Kin.
The Brush of Timber I guess you know about. The Dryad's have been struggling to reclaim it from the Borc Cross Malitia from the North, but they are so weak in military that the Tree-kin's quest seems hopeless. We may end up claiming it with the defeat of the militia, or the Borc may end up with. Who ever does, they may control life and death with a touch of the brush. Very dangerous.
Finally the seventh artifact you would have no way of even imagining. It is called Drin's Cube and it is strange and beautiful in design. The Felf call it an elaborate Tesseract and have varying illustrations of it. From what I gather it holds no earthly shape, but it's properties are also useless without outside power. It can imbue magic into any item. Avoid it, tho. Only Mouse-Kin seem to be able to touch it without succumbing to eventual insanity. The Felf hold it, but I know not where and although friendly to the Mume, the Felf laughed at my request for it's location.
It seems strange that the Mume and the Effee have not one of their own Remarkable Treasures, but the whole of Mash'ta recognize both as Great Races despite this. May the Living Goddess grant such boons in the future. I can't guess what the Effee's treasure would be, tho.
Counsil-Effee Pin-Drop, I hope to see you soon, my friend. When I return to Annalow, I have tales to tell you. In the mean time, please enjoy my copies of the Remarkable Treasure designs I have made.
-Letter intercepted by Borc Cross Malitia, 1999 years from Zero Day.