Cost: 1. XP: 2.

Choose a card in your play area or reveal a card in your hand. Search your deck for another copy of that card and draw it. Shuffle your deck.

"... all life is only a set of pictures in the brain, among which there is no difference betwixt those born of real things and those born of inward dreamings..." - H. P. Lovecraft, "The Silver Key"
Romana Kendelic
Dark Side of the Moon #205.
Lucid Dreaming

For everyone's benefit, here is a list of the cards that most obviously synergies with Lucid Dreaming (as of Dream Eaters). Please mention any that I miss out in the comments:

Signature Cards:

Stack-able Hand Assets:

Disposable/Temporary Assets With Persistent Effects:

Most of the Myriad Cards:

Cards That Synergies With Themselves:

And that should about be it. Of course Lucid Dreaming has additional functionality outside of these cards; drawing the second copy of your 5xp sink or your assets with limited uses is always a good thing. And of course, not all of the cards presented are particularly powerful with Lucid Dreaming (e.g. Knife); this list it just a time saver for everyone who wants to know where Lucid Dreaming goes above and beyond a card draw.

Lucaxiom · 3388
a) Yes you can trigger two copies of Survival Knife on the same attack as they are responses on two different cards. b) why would Hot Streak 4 and Expose Weakness 3 not make the list? — slothgodfather · 7
Expose Weakness (3) reduces the fight value of an enemy to zero. A second Expose Weakness (3) would also reduce the fight value to zero, AKA make no change at all. As for Hot Streak (4), I'll admit my reasoning is quite tenuous; essentially, you won't really need one copy of Hot Streak (4) to trigger another copy, as the cost of 3 resources is affordable. Hot Streak (2)'s 5 resource cost will generally need assistance from another economy card; it doesn't have to be another copy of itself, but it can be, and thus is included on this list — Lucaxiom · 3388
I think it's also quite good for various Talent Assets which you are allowed to have 2 copies of in play. I was thinking cards like Pathfinder, Fieldwork, Drawing Thin, High Roller, Pickpocketing, Well Prepared, etc. Whether it's really worth 2XP, and 1 Action/Card/Resource just to draw the 2nd copy remains to be seen. — Faranim · 351
In anyone with seeker card access, the full-deck-search means a guaranteed Astounding Revelation trigger (or Occult Evidence, if you're Mandy), which is significant value. And of course, Mandy can run this to grab the 2nd & 3rd copies of Segment of Onyx with her special ability, which is pretty rad. — NatesPromNight · 635
It also guarantees a Shocking Discovery trigger for Mandy, if she hasn't dealt with that yet. — CSerpent · 107
You missed out Dream-Enhancing Serum, which will draw you a second card as you reveal both because Lucid Dream specifies its a card draw to which you can react. — The_Wall · 252
Your discard pile is also in your play area. — Dis · 1
@Dis: Nope. Discard piles are specifically out-of-play areas, which are contrasted to players' play areas, which are (logically enough) in-play areas. See "In Play and Out of Play" (and "Discard Piles") in the Rules Reference. — Tamsk · 1
I'm not a huge fan of Empower Self, really. But at least you can find the other versions with one of them in hand/play and Lucid Dreaming. Although it's making a slow, expensive and clunky card even slower, more expensive and more clunky. — olahren · 2036

Can you use this card to look for the same title, but different level?

Let's say you have 1 copy of Shrivelling (0) and 1 copy of Shrivelling (5) in your deck.

Could you use Lucid Dreaming to find the other one?

That would be lovely for Mystics as it is a spell and therefore you can find it with Arcane Initiate.

Valentin1331 · 15258
Yes. You can check the RR for "Copy". — toastsushi · 62

If you are cursed with a bad luck stat this is s great card.

First backpack whiffed and didn't find your weapon? Use this and find the other.

Have a double drawing thin build but terrible draw to find it? No problem.

Drew the bad version of an upgraded spell in your deck? Find the good one.

I think the best thing about this card is the consistency. For two exp and an action this becomes any card you want. In a game where building well and early can make all the difference, this provides that.

drjones87 · 65
The problem is that you need to have drawn the other card. In case of combat assets you can usually afford to wait until you draw the other copy and I'd rather have One-Two Punch or Spectral Razor in my deck instead of Lucid Dreaming and spend the action to deal with a problem than search for my second asset. I think that this card has it's own niche as a very specific tech/synergy card that works well to find copies of cards that synergize with themselves (Three Aces, Segment of Onyx, Tony's 38 Long Colt), or to trigger the reaction ability on your Research cards. Also note that this card has no icons, so it becomes a dead draw if you have no search target. — PowLee · 13

Lucid Dreaming plus Mandy Thompson plus Segment of Onyx means you can trigger the search aspect twice, so any time you find a single Segment of Onyx, if you have Lucid Dreaming then you will automatically be able to find the other two segments, and assemble Pendant of the Queen.

In fact, if you have copies of Astounding Revelation in your deck (which with Mandy you probably will), then you'll also gather the 2 extra resources you need to play two of the Segments. So a net cost of 2 resources and one action would get you the Pendant of the Queen. Something even worth doing if you are engaged with an enemy and need to automatically evade it!

Obviously you'll have had to clear out your signature weakness Shocking Discovery beforehand, but that's what Research Librarians are for!

Its very feasible to be able to assemble the Pendant of the Queen 3 times in a scenario with two Lucid Dreaming and even an extra two times with Knowledge is Power.

Its a perfect but unlikely play, but thinking about it, Knowledge is Power is also fast, so if you have all three in your hand you could find every Segment; grab 2 resources from Astounding Revelation; play every Segment; deploy the Pendant; and evade the big nasty enemy, ALL without using a single action!

Phoenixbadger · 178
How is KiP helping here? It doesn't work on Lucid Dreaming, not on the pendant. Am I missing something here? — PowLee · 13
Lucid Dreaming is a spell so that's where Knowledge is Power comes into play. However, KIP only works on assets and lucid dreaming is an event. — LaRoix · 1595
It's a spell ... but not an asset ! — AlexP · 201
Oh yeah. Still good pairing with Mandy :-). — Phoenixbadger · 178