TasksA pile of landscape cards; they all cost $2, but don't use up a buy. When you buy one, you put it in front of you; it has an Objective for you to meet, and as soon as you do, you get a Reward and put the card back in the pile. No need to shuffle the pile, players can freely look through it and pick one
or more. Only one Task allowed at once.
Being landscapes, they can't enter the deck or have their costs reduced. Possibly means this idea disqualifies? These don't have to be attached to any mechanic, just include them whenever, but a type on Actions could help ensure more of the Tasks can actually be done. (In reality, I may include this idea in my Dynasties set so they would be included if there are 2 or more kingdom cards from the set selected).
8 ideas for Tasks here, probably 2 of each in the pile?
Purge
Objective: Discard 5 or more cards on your turn not during Clean-up.
Reward: draw to 6 cards in hand.
Escape
Objective: trash a card with no-one revealing a copy (when a card is trashed, players may reveal a copy from their hand).
Reward: 4VP.
Seize
Objective: gain 3 or more cards on your turn.
Reward: 2VP.
Collect
Objective: get $15 or more during your turn
Reward: 2VP.
Compete
Objective: reveal a hand of 5 or more differently named cards
Reward: 2 Coffers 2 Villagers.
Plot
Objective: at the start of your turn, guess the top card of your deck correctly (name it, then reveal the card).
Reward: +3 Cards.
Register
Objective: have 5 differently costed cards in play
Reward: + $4
Capture
Objective: start your Buy phase with 2 or more Actions left
Reward: gain a card onto your deck costing up to $5.
Just a first draft that explains the premise. Nice one-offs you can work toward sometimes, extra engine options other times.
Edit: rule of one Task at a time only, was meant to be there but forgot