Gambit.
Fast. Play during any investigator's turn, except during an action.
Immediately take an action as if it were your turn. This action does not count toward the number of actions you can take each turn.
TL:DR, nice effect, there is not a character around that doesn't want this in their deck. Problem is that a free action, at that cost and a cardslot, probably not be what the doctor ordered, therefore it'll rarely see play.
Swift Reflexes is a free action, it even gives you some leeway in when it happens, sneaking actions into someone else's round, useful for example to grab an enemy or snipe a persistent encounter card so that another character might do their thing better. An extra attack, a move, actions are good.
But the problem is the economy, you get 3 actions per turn for a dozen+ turns every game "for free", paying 2 resources and a card is steep but fair, but can you spare the card slot?? You need those slots to build that carefully orchestrated deck, how valuable is that lone bonus action over, say, an extra card draw from a boosted action with one of the neutral skills on it? Do you have enough weapons? Most cards are about generating extra success value from every action, "More success in less actions", a flat +1 action is therefore weirdly often unhelpful, at such a steep cost that is.
Swift Reflexes has 2 on there, so it might reasonably replace a Manual Dexterity, run them together with Backstab to have a pretty good range of options.
It's not a bad card, it's mostly a case of an effect that in of itself is so small that I wonder if it'll be worth it's slot, at that price too. I would be glad to see an XP version that grants some bonuses during that extra action.
Edit: Some more experience.
I started finding more use for this card, mostly outside the faction. folks tend to pay through the nose for stuff, especially , which is where non-repeating extra actions really shine. Characters with large bonuses already will find Swift Reflexes much more routinely useful then those with 3 or less. Tony Morgan and Leo Anderson for example.
2 resources and 1 card for 1 action, but 2 cards and 1 card worth 3 actions, so 3 actions for 1 action? Not an impressive card among all those rogue cards providing action. But when export to other factions with Versatile, this ability become priceless. Seekers draw cards so easily, that you can almost consider cards as free. So 2 resources for 1 actions now? If there is any card can get resources as efficient as 1 action (you don't have to count in any cards spent!) for 3 resources, then the combination will become 1 free resource! And then you just use the free resource for more actions! Here is a deck for example.
This card is esentially "Skids" O'Toole's ability on a different time window, and Skids' ability isn't considered that great on its own. Here you are sacrificing on top of that a card slot to be able to take an action, and you need to draw the card first too: it's not good.
There are some interesting interactions you can make with this card, like having someone fight an enemy, then use this card to pull them off with an engage action so that they can take the rest of the turn doing something else, getting them ready to be fought or evaded by you or tanking the damage for someone else, but even then, not really worth it.
The main issue with this card is that the action you take must be succesful to be worth the resoruces you play, so the best use for this is ironically to take testless actions overall, or in scenarios where you need LOTS of actions
It's not terrible, and I can see being slot as fodder to get to the max legal deck size, but unless you do some real good strategic thinking on how to make the most of an action taken during someone else turn, this is probably one of the first cards you are gonna replace with a leveled up one or with adaptable