Gambit is one of the mini-expansions for the Star Realms deck-building game. This review is written assuming that you totally know what that means.
Like most expansions, this pack includes only 20 cards... and only 16 of those are playable cards. But they are good cards. Thirteen of these cards introduce a new game mechanic, the 'gambits'. These are simply a number of event cards that are shuffled to each player to play as they see fit; they do not go into the player's deck, but are set to the side, face down, to play when desired. Many of them are one-shot: "acquire a card of cost 4 or less without paying the cost"; "gain 8 health and draw a card". Others are ongoing: "each turn gain 1 attack"; "whenever you are attacked, reduce damage by 1".
While these are simple and straightforward, they are well balanced and add to the game-play. They can also help players get out of a rut; if you normally play heavy on the defense but get a gambit that supports an attack strategy, you're not likely to ignore it. I have found that two gambits per player works quite well, but the rules leave it up to you how you would like to allot them.
Additionally, there are three copies of a new ship, the Merc Cruiser, that gives 5 attack and acts as an ally to any one faction of your choice. This is a good card, but at a mere 3 gold it is under-priced.
And finally, three cards are 'challenge' cards, that give alternate rule sets and scenarios for solo play and co-op play. I have not tried these yet, but they look fairly challenging.
Overall, this is one of the better expansions for Star Realms. It is generally about $5, and adds some new dimensions to gameplay, ranging from the intuitive and fun gambits to the somewhat more complex rule sets. This, along with the Star Realms: Crisis: Events, appear to be the most interesting expansions out so far, and perhaps the only two mini-expansions that are clearly worth the price.