I've had this idea for a sort of match 3 card game with a farm theme.
Players would have a handful of cards with various vegetables on them.
There would be an empty 7x7 tile game board that looked like a tilled field.
Below the game board, there would be a number of 'goal' cards, with various arrangements of vegetables on them. More difficult patterns could be worth more points.
Play would start with the top card of the deck being placed in the middle of the field.
Players would place a single card at a time on the game board (only in spaces adjacent to cards already on the board), attempting to match patterns shown on the goal cards. After a player plays a card, they draw a new one.
When a player completes a pattern, they take the goal card for score-keeping purposes, and the cards that were used to make the pattern are discarded.
Play would continue until a player reached a certain score.
I am seeing this more as a kids/family game due to the simple nature of the gameplay and theme.
EDIT: I've attached a couple images of cards to show the idea I had for them.
Players have common goals. I think it makes it a bit like tic-tac-toe, where each player knows what pieces need to be placed and they have to balance blocking the other players while placing cards to achieve goals themselves.
Players will have a hand of cards (not sure how may cards per hand though). An option to mulligan once each turn could be a good addition.
The goal cards and veggie cards will be separate decks, since the goals will be common to everyone.
I don't think constantly swapping goal cards would be great. It could lead to goals being worked towards, but never fulfilled very easily. It could also do the opposite where a new goal card is revealed, and fulfilled instantly.
Thinking about a goal being fulfilled instantly does lead to an interesting mechanic though, where players could get 'combos'.