An obviously great choice with Eyes of the Dreamer & Breath of the Sleeper but the really spicy combo I'm surprised nobody has mentioned yet is having Spectral Shield repeatedly eat the 3rd charge off of The Red Clock to take 2 additional actions every single turn!

That's 2 Leo De Luca's with even more soak than the Leo's would normally provide all for 1 action, 2 cards, 3 resources, 10 xp and an accessory slot assuming you can find 1 damage or horror to soak up every turn. The most obvious choice would be to drop the Spectral Shield on a Guardian's Beat Cop or Field Agent. Alternatively, if there happens to be an Internal Injury or Chronophobia in play, your team can laugh off the fact that not only did a basic weakness just get cancelled out but also became a combo enabler in the process. And barring those more convenient options, you can always toss the shield on yourself and just run a copy or two of Forbidden Knowledge to give yourself a useful self-horror outlet for those turns you would otherwise struggle to find an enemy or treachery to hurt yourself with (which serves as a not half-bad excuse to run Adaptable so you don't actually have to put the Forbidden Knowledge's in your deck until you've purchased the Red Clock).

Theoretically, anyone with Rogue 0-5 access can run this combo using Versatile. Of course, Jenny Barnes can do it by taking the Shield as part of her splash. Though the best choice by far is Sefina Rousseau, who can not only run both Red Clock (5) and Spectral Shield as part of her normal deckbuilding options but has a better chance of seeing the clock and shield early with her 13 card starting hand. And she can keep the shield fed by utilizing a full array of charge based Mystic spells. That's important as the one downside to this combo is that Spectral Shield is not an optional effect. You MUST spend charges if any are available to be spent which means you'll likely want a secondary asset with charges to pull from anytime the Shield ends up eating more than 1 charge per turn.

The main, general-use purpose of this card is to gain resouces while killing your Arcane Initiate, David Renfield, or other Doomed Ally so their doom diesn't cause the agenda to flip early.

You can hope to kill them in other ways during the Mythos phase, but this just makes it a bit more guaranteed

I believe using Robert to play a Remington Model 1858 will net you two free shots if you chose to play it. (I'm not entirely sure if it gets you a 2nd free shot if you discard it, as it hasn't 'entered play'?) In any case he's great for a Fist-based gun fighter rogue. (I'm guessing he was designed to be Michael McGlen's friend, but he seems quite helpful to Tony Morgan too.)

I have couple questions with this card.

1. Can you play the card like Refine one more time if you transfer to another investigator? The text on Refine shows "Max once per game for each Investigator"

2. I understand the damage will keep same after transfer. How about if the damages on original investigator are over the cap of the transferred investigator?

I think this is a descent upgrade to an already good level zero card. It does everything the level zero version does and on top of that ...

... it gives an additional skill point to pass the test.

... it heals both damage AND horror from an ally.

... it allows using this skill card in ALL skill tests (including agility tests and money test)

Is it a "must include"? Probably not. But if your investigator likes to evade enemies or if your deck includes cards that put both damage and horror on your allies, then this upgrade might be worth the 4 XP's for a pair.