tcg

You could have sets themed after particular Expeditions/locations. I would recommend having a 'limited' format akin to MtG wherein only the past few expeditions are legal; I find that this helps prevent power creep and creates a better environment for sealed/booster drafts.

The battles are flavoured as expeditions competing be the first to a treasure or what have you.

The win condition to be the first to reach the Treasure. Both teams start at 0 points and go up. You gain points by knocking out the opponent's Pokémon, putting yourself forward the same number of HP they had, or by attacking your opponent directly, converting damage directly into points for yourself. The first to reach [x] (number yet to be determined) points would win.

There are a few kinds of cards. Expeditioners (powerful Pokémon who are members of Guilds), Pokémon (flavoured as recruited in the dungeon), Equipment (permanently equip to Pokémon), Items (single-use cards that can be used in place of a Pokémon's move or attack), Expedition (event cards that function similarly to Trainer cards), and Terrain (can affect the world or be placed into lanes; see below).

You have a pool of Supplies cards which represent your Expedition's food sources. Akin to the mana pool from MtG, Supplies come in one of five flavours (spicy, dry, sweet, bitter, and sour) and you can add one per turn to your Supply Cache. Supplies are used for recruiting Pokémon and calling Expeditioners into battle, and may be required for certain other cards to work. You may add one Supply card to either your pool OR to a Pokémon on the field once per turn.

The field is divided into lanes. During each turn, each Pokémon can move into an adjacent lane, attack, or use an item; they can only do ONE of these things, and once they had taken their turn, they're turned sideways. Some moves can only hit an opponent in the same lane; others can hit adjacent lanes, etc. As long as a Pokémon is in a lane and is not dead, it will take any damage from Pokémon that attack that lane unto itself. To attack an opponent directly, the lane in front of you must be clear.

Pokémon cards are similar to Pokémon from the current TCG. They have HP and typing, with resistances and weaknesses to other types. One difference is that all game types are represented in the TCG. Pokémon typically have moves and may have abilities. Instead of energy, Pokémon take Supplies from the Supply Cache when they are placed down; they would have a certain cost, for example "2 spicy 1 any". Most moves consume a Supply card; the card is then returned to the Supply Cache. If a Pokémon is out of Supplies, it is unable to use moves, move, or use items. There are certain item cards that provide extra Supples when attached to Pokémon, but these extra Supplies do not return to the Supply Cache. Note that a Pokémon need only be in a lane to take attacks; it can take an attack regardless of whether or not it has already acted that turn.

Expeditioner cards also have HP, but they do not have moves, per se. Instead, they have various abilities that greatly affect the field. Instead of using Supplies for these abilities, they have Bond tokens, which represent their friendship and trust in you, the Expedition Leader. By doing things to increase their Bond to you and then cashing in those for abilities, they can turn the tide of battle. They take Supply cards to call into battle, but return the Supplies to the Cache once they are knocked out or reach zero Bond. They're comparable to planeswalker cards from MtG, but are more directly involved.

Equipment is akin to that in the Pokémon Mystery Dungeon games. Each Pokémon can carry one piece of equipment at any given time. Equipment may require Supplies to equip or unequip or to activate its abilities. Equipping does not count for the Pokémon's action for that turn.

Items are, again, similar to those in Pokémon Mystery Dungeon. They're akin to Expedition cards but are used by a specific Pokémon, and use up that Pokémon's action for the turn. They can have a variety of effects. A few Items are not single-use but multi-use, but in general they'll be used and resolved. Certain Items can be used as a reaction, and some Items have additional effects if they are thrown rather than used.

If a Pokémon has not moved during its turn, it can move to an adjacent lane in response to an attack by an opponent Pokémon facing an empty lane. If Opponent Pokémon is in Lane A, and you have no Pokémon in Lane A but one in Lane B who has not yet gone that turn, Pokémon B can move into Lane A to take the attack.

Expedition cards represent events that occur during an Expedition and take on a similar role to Trainer cards. Some may be cast instantaneously, others only as a reaction. One thing to note is that the "Stack"/"Chain" exists here, wherein players can respond to others' actions by activating their own abilities or cards, which is resolved on a last-in-first-out/first-in-last-out basis. Expedition cards typically are not placed in lanes since they are resolved and then are discarded, but Expedition cards can also be placed face-down in lanes and activated later (see below), oftentimes to play mindgames with the opponent or to safeguard from hand-discard effects. Some Expedition cards may occasionally be made permanent and those would go into an appropriate lane.

Terrain cards come in two main categories. There are 'world' cards which come into play and remain in play unless removed (rather than a one-use card), which typically alter something about the general world. Multiple of these can be active at a time, though any that would contradict have both effects nullified. The second type are cards that, similar to the Expedition cards, placed in lanes face-down behind one's Pokémon and activate in response to attacks. All of the Traps in the regular Pokémon Mystery Dungeon games would go in this category.

You can place Pokémon, Terrain, and Expedition cards face-down, and only pay for their Supplies when flipped. Conversely, if you place down a Pokémon without being able to give it the correct Supplies once it is flipped over by an attack or card effect, that Pokémon is instantly K.O.'d.

Things such as status effects would also exist, though would be different than the TCG variants. Burn would cut all attacks in half for the specified number of turns; paralysis would allow the Pokémon to attack/move only every other turn; freeze would stop Pokémon from moving; sleep would prevent Pokémon from attacking OR moving; poison would do 20% total HP damage rounded down each turn. Conditional status effects would come up as explained on the card, but the purpose is to remove as much "flip a coin" stuff as possible.

So, to sum it up, this game would focus on positioning and resource use with a heavier bearing on strategy and skill than luck.