Lily Chen with a pair of Butterfly Swords, particularly the level 5 version, should probably give this a look. Intrepid is quite strong if it can be leveraged for an extended period of time. That's normally a problem in guardian, because they don't have much action generation outside of Galvanize unless you're someone like Leo Anderson, and even then this is a niche card. But the problem isn't the lack of actions in a turn; it's the limited number of skill tests you can take. Enter Lily, master of the thousand palms, who can unleash a flurry of strikes, compressing an enormous number of tests into just three actions. And it's in the eye of that tempest of blows that this card finally begins to sing.
Let's break it down: Opting to go with Lily's agility signature, Balance of Body, grants her three fight or evade actions for the price of one, which translates to up to five tests in a single turn. Already this card has the potential to do work. If you add in Butterfly Swords (5), you can take two tests per fight action, effectively doubling the utility of this card even without action generation. Swords and Balance together combine to grant upwards of eight tests. That's suddenly a lot of value. Toss in Galvanize for an additional two tests from Swords. You get the picture.
As a bonus, the second test on Butterfly Swords adds your agility to your combat, effectively netting you +2 from Intrepid. The doubled bonus also applies to a number of other Lily-tailored combat tricks like Sweeping Kick and Fang of Tyr'thrha meaning you can really go beast mode during your turn. And you're Lily, so you should be going beast mode.
These synergies justify giving Intrepid a long, hard look.
The other obvious weakness of the card--that it requires a successful willpower test to trigger--is largely mitigated by Lily's deckbuilding and (at least this) playstyle. While most guardians, even those with high willpower, are dependent upon the whims of the encounter deck to utilize Intrepid, Lily, as a quasi-mystic, can run a number of useful cards that can prompt a willpower test on command. And while normally cutting into your turn by "wasting" an action on a willpower test to trigger this would hurt, Lily's enormous test-compression potential offsets this downside.
Long story short: Take this card in flurry of strikes Lily and play it during a mega turn to help you crush tests. Also, pro-tip: use Balance early to maximize the number of tests you take with it Broken side up. You never know when you might get lucky and draw an elder sign, meaning you can use Balance twice in a single turn. The only thing better than eights tests in a turn is ten.