Shadows of Montmartre
Pattern: The Elders say that Corwin's Pattern worked much as Corwins Memoirs describe the Amber Pattern, with some important differences. They suspect that these differences were due to Corwin not recording the full truth, rather than differences in the powers themselves. But they don't really know, as none of them have taken the Pattern of Amber. Ever since Le Schisme, they have found it difficult and risky to use Corwin's Pattern. It's been years and years since they made any efforts to use it. PCs who have "Pattern Lore" have probably made a handful of efforts to use the Pattern in a very minor way. I expect that one of those met with some small degree of success, and one other of them resulted in a headache that took days to go away.
Logrus: Precious little is known. "Basic Logrus Lore" includes very basic knowledge of both Logrus and Shapeshifting. But not a lot of knowledge is available.
Shapeshifting: See Logrus. Additionally, items with additional forms do not use anything like Shapeshifting to achieve the additional forms. Or so everybody thinks; their knowledge of Shapeshifting may not be deep enough to tell. There are also creatures like weres that transform, but they are quite rare. They are not thought to be powered by anything like Shapeshifting. The most well known of these are the alpine wolfmen of Carpathia. Even those are considered old wives' tales through much of the Rose Circle.
Trump: Since Le Schisme, Trumps are unreliable and a bit dangerous. Though decidedly less dangerous than Pattern, they are still dangerous enough that they have been more or less unused for years and years — though in a true emergency, they would probably be pulled out. Since Le Schisme, even Jean-Paul has found it very difficult work to make a trump card. His failed attempts vastly outnumber his successes, and even the 'successful' cards are fragile and unreliable. "Trump Lore" means that you've probably made a good 15-20 trump calls, and have made about a handful of trump sketches — one or two of which even worked once before being expended. PCs without Trump Lore have probably made a trump call or three in their lifetimes.
Sorcery: Works much as in standard ADRPG. Without an artifact to aid them, a sorceror may hang a number of spells equal to half their Psyche, rounded up. Approximately, you know (a little give either way, depending on the complexity of the spell).
Artificer: This is the creation of magical and technological items. The number of items a character may have in existence at any given time is limited, as they require effort to maintain. The Psyche of the creator has some effect on how many items he can maintain long term — with a bonus if the character has purchased improved Endurance. Player characters who have purchased Artificer may begin the game with previously completed items — please discuss specific items with the GM.
At any time, an Artificer can free up maintenance capacity by just making a new item and stopping the maintenance of the old one, which will decay in under a day. This gives them a short term capacity of double their long term capacity, and they could make a single short term item of that power level.
Also, an artificer who is incapacitated may not have the energy to perform needed maintenance, and some of their items may decay.