Stella's Zero Skill Needed

The gameplan is simple at the start - focus Flashlight on low-shroud areas for easy tests while Old Keyringis better at higher-shroud areas since it only uses charges when succeeding. Scavenging allows you to get your hand slot items back when they're used up. NOTE: Flashlight is NOT automatically discarded when empty. Fine Clothes are there for the additional health on the cheap, and they can be regained with Scavenging if needed.

For upgrades, priority #1 is Quick Learner for its ability to ensure a fail on action 1, granting you Stella's extra action and the ability to use the difficulty reduction on two actions a turn instead of just one. With two Quick Learners, you can have a turn be:

1. Fail an investigate, draw a card with Rabbit's Foot.
2. Filler action, take a resource, draw a card, move, replay a hand item, or whatever else.
3. Flashlight/Old Keyring for a 0-difficulty clue.
4. Another 0-difficulty clue. This is because even a 2-shroud test with two quick learners has a difficulty of 4, allowing a guaranteed fail for Stella. As an added bonus, the failed test on #1 can have Take Heart added to it, and might get a "Look what I found!" play to increase clues-per-turn to 4 instead of 2.

After Quick Learner, the next priority upgrade is switching something out for True Survivor. Depending on the group and campaign you'll probably need different things, but Overpower is a solid choice to switch out. With True Survivor, you can use Take Heart on action #1, then get it back on action #2 with True Survivor, as well as a Resourceful and a Neither Rain nor Snow. Action #3, if guaranteed to succeed, can then have Resourceful attached to get True Survivor back, giving you Mythos protection with Neither Rain Nor Snow every turn.

Survival Instinct isn't necessary for the deck to function, but is a good addition since this Stella doesn't fight. Being able to evade multiple enemies in one action can save several actions, and getting a free move in addition is a big bonus. Note also that you can play it on other players, increasing its usefulness. Manual Dexterity can be switched out for this when you have spare XP.

Relic Hunter allows you to have two Rabbit's Feet in play at the same time, potentially giving you 5 cards a turn (two from Take Heart, two from Rabbit's Feet, 1 from upkeep). This drastically increases how quickly you get your winning combo going.

Any spare XP beyond that simply goes into upgrading your kit - A Test of Will becomes much stronger with XP, while Lucky! is simply slightly better with every upgrade. Other cards in the deck can also use upgrading, obviously.

If your collection has some permanent you think would be useful to the plan those are likely fine additions. If I had to say one thing was a weakness in this deck it's mobility - with action one being the best at triggering Stella's ability to get extra actions, and #3 & #4 being important for getting things done, it mostly just leaves action #2 for moving, and you might want that one for playing True Survivor. It all depends on the situation you find yourself in, of course, but you should mostly consider the first action as being free if you can guarantee you'll fail. Essentially, the deck's weakness is that you want to do things all the time. And you can't fight.

If you want a bit of fun, consider In the Thick of It and Versatile to start with a bigger deck and the ability to add cards like Vicious Blow to the deck. You might not be a great fighter, but you'll be able to draw more cards before returning your discard pile to your deck (allowing less horror) while also reducing the risk of drawing a weakness at the cost of having less consistency. But it'll allow you to play more situational cards, especially if you have a seeker on the team that can help you search your deck.

Overall, this should work really well at getting a stable stream of clues so long as you have a bodyguard of some sort to handle enemies, especially hunters, that might be bothering you.