I know this thread was not meant to be comprehensive, but given that we have an ongoing Fan Card Mechanics Contest, I wanted to collect more of these mechanics, even if only for my own use. So I have been trawling through the past several pages of Variants and Fan Cards posts, looking for any fan mechanics. I can't say 100% I didn't miss any, but I think I have got most (if not all) of them, going back to about the beginning of 2020.
Here is my list of fan mechanics not currently in the Atlas (and which have not been featured in a Fan Card Mechanics contest):
Luxury cards and the Wealth type (from DunnoItAll's Dominion: Middle Ages) -- Luxury cards are an additional Supply pile that gets added when a Kingdom pile has the Wealth type; they stay in play and give a vanilla bonus at the start of each turn.
Gems and Gemstones (by DunnoItAll) -- Gemstones are player-specific landscapes that function as a kind of modified Coffers mat, the tokens on which can be returned for a different amount of $ depending on some external condition. Gems are the tokens.
Setting aside a Kingdom pile as a non-Supply card (from Something_Smart's Roots expansion) -- the cards are gained by an Action or Event, which also modifies how it gets played (see Judge, Pioneer, Construct, Witchcraft).
Double-face cards (by Carline) -- these cards are set aside at the beginning of the game, and are played using either a card (Guildmaster) or Way (Way of the Beast)
Harms (from Something_Smart's Rivalries) -- piles of Junk cards that do harm to a player during Clean-up (in games using them, players must reveal their hand during Clean-up)
Currency (from Jupaoqq's Dominion: Dynasty) -- Coins that can only be used to buy a specific type of card (i.e. ActionCurrency, TreasureCurrency, and VictoryCurrency)
Monsters (by Marpharos) -- a harmful landscape in the middle of a split pile that are "defeated" using Raiders, a resources handed out by the top card in the pile (which has the new "Adventurer" type); when the Monster is killed, a Reward is given to the players based upon their participation in defeating the monster
Heritage cards (in DunnoItAll's Dominion: Subterfuge) -- DunnoItAll doesn't really explain how these work; given that each Heritage card accompaies a Kingdom card with the Heritage listed like an Heirloom, I presume it works like an Heirloom, but replaces an Estate instead of a Copper (though I would appreciate DunnoItAll correcting me if I am wrong).
Money Bags (by herw)--cards with an a bonus on-play effect that requires putting basic Treasure cards from your hand under them as a form of payment
Adventurer Cards (from Udzu's Dominion: Swords & Sorcery) -- "a sort of cross between Heirlooms and Reserve cards," each of these is included when a certain card is in the Kingdom; they start on a player's Adventurer's mat, and stay there until thery are called by meeting some condition. They are then discarded, and become part of a player's deck. They are modified by Equipment landscapes.
Missions (from Udzu's Dominion: Swords & Sorcery) -- Objectives that, when completed, give the player a bonus
Janus cards (by emtzalex) -- two-sided cards (they have one face, but one is right-side up and the other is upside down), which, when played, give one effect to the player playing it, and the other effect to each other player.
Equipment cards (by gambit05) -- Like Heirlooms, these are added to the game based on the presence of certain Kingdom cards; they start out of the game on "stand by" mode, and enter the game when "Equipped" by a player meeting certain criteria. A subset of these have a "Cabinet" type, which go onto your Cabinet mat and enhace the play of other cards while there (see Kingsman). This is an update of an
earlier post, which also had
Morale cards.
Henchmen + Underlings + Jobs (by spineflu) -- Henchmen are tokens that go on a Henchmen mat, and which are given by cards with the "Underling" type. In games with an Underling card, a Job (or maybe more than one) is added to the game. During a player's Action phase, they may pay 1 Action and 1 Henchman token to play the Job.
Carts (by gambit05) -- Cart is a non-Suppy Action card that gives +2 Actions, +$2, +1 Card per empty pile.
Territories (by scott_pilgrim) -- landscapes that give Project-like bonuses, but which can only be held by one player at a time; in order to take it away, another player must pay more than the current holder paid the previous time
Allies (by MrHiTech) -- "Allies are a sideways card type. They go in your sideways deck, and start in the supply. When you buy an Ally, it goes in front of you, like an Artifact, and you benefit from it while its in front of you. Another player can buy an Ally from in front of you, and then they put it in front of them. There is only one copy of each Ally."
Buy type (from X-tra's Odyssey) -- Cards with the Buy type can't be "obtained in any way outside of your Buy phase."