Orrery of the Wanderer

Created by Pendel Codagio during The Great Serpent War, then subsequently dismantled for being too powerful ("even if the world were safe from Turmoil, it wouldn't be safe from the Orrery"). It is now in seven pieces, six of which have known abilities of their own and the seventh doesn't even have a name.
The House of Cards and The Hounds Guild are both searching for the pieces. Alfalfa claimed that the House of Cards had found three, but one of them ran into a problem during transport and has been lost.
Alfalfa also claims to have touched a piece of the artifact, and has been having visions ever since. She also appears to genuinely remember Dennis Donahue being in a different location than where she told the party he was before. Not only that, but she also appears to genuinely remember telling the party that that was where he was.
According to Annu Adabra, it is forbidden to reassemble the Orrery because of its power.

The Rotor of Return

One of the seven pieces is called the "Rotor of Return". Kerro "Burnclaw" Schene was discovered to have been carrying it around.

AI, p221

Rotor of Return

Wondrous Item

Very Rare Requires Attunement

While attuned to this device, you have a +1 bonus to Constitution saving throws. You periodically receive flashbacks of old memories, and you can unerringly recall any event that took place within the previous 30 days.
Borrow Object. You name a mundane item with a value of 50 gp or less and it appears in your hand or at your feet. This can be any item that appears in chapter 5, "Equipment", of the Player's Handbook, or any similar item selected with the DM's permission. The summoned item is transported to you from somewhere else in the world, but it is generic in nature, so that you might call for a longsword but you cannot borrow a specific creature's longsword. The item vanishes 10 minutes after it appears. Once you use this feature of the rotor of return, it cannot be used again until the next dawn.
Recall Code. As an action, you can set your current location as a point of return locked to the rotor. Anytime thereafter, you can use a bonus action to teleport to the rotor's point of return as long as you are within 500 feet of that point. Once you use the rotor of return to teleport, this feature cannot be used again until the next dawn.
Part of a Whole. While this component is not installed in the Orrery of the Wanderer, its magic might function sporadically or with unpredictable side effects, as determined by the DM.

The Chronolometer

The Dimensional Loop

The Far Gear

Described by the DM when Dwardazik Stoneturner Boulderhearth grabbed it in Session 127:

A large glass orb. Looking through its internals, it's as if you can see through infinity itself. It sits upon a pedestal of other gear-like complicated mechanisms. A little half-crescent of more gearwork pops up, and a little moon sits atop it, as if staring down into infinity.
All told, it is about one-foot in diameter.

The Timepiece of Travel

The Wheel of Stars

(The unnamed seventh piece)

This is theorized to be the piece that binds the other six together.

Item type

Unique Artifact