Set collection mechanic advice

I agree with Markus. You will need some sort of interesting mechanic to facilitate your card taking. The symbols idea is nice, but you need to make it so that there are some alternatives. Perhaps the matching symbols makes set collection easier, and is not a necessary element to take a card.

Diagonal card taking can be tricky, perhaps a bit too spatial. Perhaps 2-by-2 card taking? Just a suggestion.

Some more info about the theme of your game would help.

DnDDmDb

Nice idea. Will regular suit cards be in the additional deck? Or will they be completely different sets of cards? You seem to have enough going on so that simply row or column collection should suffice. Plus, since it's a family/filler, the row and column collection should be enough. Will collecting the -1 cards still count towards scoring in that suit (So if a set of 3 Suit A cards gets you 5 points, then can you have 2 Suit A cards and 1 Suit A -1 card to get 4 points?

This seems very cool. Good luck.

This might be totally different from what you have in mind, but I thought it might be cool if in the beginning of the game, players are playing down 2 cards into "the grid," then in midgame, they're playing 1 and picking up 1, and finally in the very late game maybe they're picking up 2 cards. So you'd build the grid, then take it down, with the aim of collecting sets.

So how might I go about this? Off the top of my head:

Components:

2 Player pawns per player
108 cards

• 81 Symbol cards (use a SET deck)
• 27 Action cards

Deal some of the cards in the game out to players, put the rest in a draw pile.

On your turn you have 3 action points to spend on the following - but can choose each option a maximum of twice each turn:

• Draw 1 card
• Play 1 card
• Move one of your pawns from card to card
• Pick up the card where your pawn sits

DRAW A CARD

Simply draw a card from the deck, these cards will either have symbols that you will want to collect, or special actions you can play, such as:

• "Displace an opponent's pawn"
• "Swap the position of 2 pawns on the board"
• "Gain 3 additional Action Points this turn"

PLAY A CARD

Play a card from your hand:

• Symbol cards are played into the grid on the table, maybe you have to play it adjacent to an edge or a card already in play.
  
  • You cannot play a card on top of another card, nor on top of a pawn (or at least, not on top of your own pawn)
• Action cards are played, their effect resolved immediately, then discarded.

MOVE A PAWN

Move one of your pawns orthogonally (or possibly diagonally) to an adjacent card. It might be cool if pawns only move orthogonally, and then there's an Action card that stays in play and allows you to move diagonally.

PICK UP A CARD

Collect a card that one of your pawns is standing on.

• You cannot collect a card where another player's pawn stands.

Game End

The game is over when the last card is picked up.

Winning

The winner is the player with the most complete sets. A set is 3 cards which, for each of the 4 attributes (Color, Number, Shape, Shading), are all the same or all different.

It seems to me that there isn't any particular reason why you couldn't use the diagonal directions. Especially since the longest diagonals run past each other, and late movers may end up with three cards no matter what they choose, it seems to me that you should be able to collect cards/tokens in any direction you want.

As far as the scoring mechanism goes, it seems to me that there may be one too many scoring elements. You have a bohnanza progression, a negative value card, a set that you need to collect in order to not get negative points and a separate deck to collect from. Coloretto uses three: positive geometric progression, negative geometric progression and flat rate points. Poison uses three: negative points for potions, canceling out for the most, more negative points for poison. As a casual game, I think you could get away with three which are a little more integrated with each other as opposed to four where they operate very independently of each other.

Do you need pawns at all?

As I understand it, you lay out sixteen cards each round facedown in a 4x4 grid. On your turn, you must flip a card and then you may claim all the flipped cards along one row (horizontal, vertical and/or diagonal). Unflipped cards along the line that you claim remain there for other players to claim and the game continues... but once you claim a row you cannot participate any more.

So, players have an incentive to hold off to the end in order to see everything but if they do that they are likely to also miss out on the opportunity to claim 4 cards. However, if someone really likes three cards along a row, they can also claim it early without risking what is under the fourth card... and because you don't want to set up players to claim four good cards, there will be an incentive to flip cards along staggered dimensions unless you specifically want one row for yourself. So, in my mind, there are a lot of things to consider regarding where you flip cards and when you claim cards. Adding a diagonal claim to this should not change these constraints to player decision... and in fact, it may allow people to evade cards they don't want. But, often at the cost of not acquiring as many cards.

As far as negative cards are concerned... one of the nifty aspects of Coloretto is that you can poison someone else's well by loading them up with cards that will end up counting against them. But, you can't do it with too many cards of the same type otherwise they may simply claim those instead. So, the late game gets fairly tactical (even if strategically straightforward).

Given the similarities already in how cards are collected, I don't think you want to adopt the same scoring mechanism from Coloretto. But, it does suggest a problem with your negative cards. They aren't really integrated in a very nuanced way... they are simply cards you don't want.... no one wants them. In Coloretto, it is often the case that the cards you don't want someone else does want. So, players have to decide whether to try to keep certain cards for themselves or give them to players who don't want them.

Poison also has a mechanism that makes it so that the same card can be both desirable (if you have the most) or undesirable (if you don't). So... it's not clear where you should collect cauldrons or not. The Poison cards are just negative... but that is necessary to balance the desire to collect as many cards as you can and players have a lot of control over where they put the poison. So, I would encourage you to introduce a mechanism that integrates positive and negative points more dynamically.

I mentioned two of the set collection scoring systems, but there are also others:
Most of the least (encourages the opposite of single color collection and really only works with 5 or less color)
Poker (allows both numbers and suits, balances the value of each card fairly well and a good deal of swinginess)
Rummy (allows both numbers and suits and weights, encourages the collection of certain cards over others and is relatively accumulatively stable)
Perhaps people can think of others.

Of these, I think Rummy is the only one which allows some kind of negative score for incomplete sets. So, you might consider how the game might look with some kind of Rummy type structure. Especially if you want to keep it light.