This card is insane. Why? Because you can have two of them out at the same time.
With two of these out, every clue you drop gets you 2 free-ish clues that you can discover off of any location, ignoring shroud values.
All you do is alternate between using one research notes, and then the other, so you're always using the one with the most evidence on it. So having two of these out is sort of like having a permanent The Skeleton Key, that makes shrouds 0 instead of 1, lets you pick up as many clues as you pass by, and doesn't have to be moved from location to location... provided you can generate enough evidence.
The limiting factor here, then, is in how many clues you can drop per turn, to fuel your Research notes. Thankfully, there's a few strong repeatable clue dropping effects you can utilize:
Quick Study is by far the best option. You can have two of them in play, letting you drop 2 clues per turn, and it gives you skill boosts on your research notes, allowing you to hit such high values that you could clear out a location in a single test late in the game, regardless of what token you draw.
Dr. William T. Maleson lets you drop an additional clue each turn, at the cost of taking up your ally slot. Given that the Research Notes action isn't an "Investigate" action, you can't use Dr. Milan anyways, so this isn't a huge deal.
Captivating Discovery lets you "prime the pump", so to speak - just slam it down once you have both research notes in play, drop 3 clues, and you can get a total of 6 evidence in play, which should be enough to keep you going the rest of the scenario. The fact that this card also draws 6 cards for you on top of that is ridiculous, and also lets you dig for key cards to enable your combo if you aren't quite there yet.
Forewarned only lets you drop a single clue one time, but treachery cancellation is an incredible effect, and this deck turns its downside into an upside. At only 1xp a pop, this is an auto-include.
The only question, then, is what investigator to use this combo in. All of the key cards are level 2 or lower, so you have a TON of options you can use. Personally, I like this card in a Geared Up Parallel Daisy Walker deck. You can use Backpack and Schoffner's Catalogue to fully set up your combo on turn 1, and then just... get to discovering clues! Plus, since Research Notes is a tome, one of your actions discovering clues each turn is free!
Honestly, I suspect this card might be get taboo'd, sooner rather than later. Being able to discover almost all your clues by testing 0 instead of a location's shroud is kinda bonkers... at level 0, no less! But I'm definitely looking forward to at least ONE completely broken playthrough with this card...!