Sticky Note
Sticky Note is an artifact that lets you choose a card in your deck without Retain to gain it.
Clarification
You won't be offered this artifact if you're in the (extremely rare) situation where you have no non-Trash cards that don't Retain in your deck.
You must choose a card that currently doesn't have Retain. You cannot apply it to a card that can upgrade to lose Retain.
If applied to a card, it will remain if you upgrade the card (or sidegrade it with Annoying Debate).
Strategy
This artifact can help improve the consistency of your deck. Notably, Max's starter deck has one decent target for this already - Admin Deploy. Worst case scenario, if that card simply isn't good for your deck, adding Retain to it is sort of like removing it - at least you won't be drawing it again after the first time.
But Admin Deploy, especially when upgraded to its B version, can become a rather useful way of playing expensive cards like Clean Exhaust, Ace, and others. Alternately, if you have an expensive target for Admin Deploy like these things, you can add Retain to them to make them easy targets for Admin Deploy - their Retain means they go to the left side of your hand after the first turn you draw them, which conveniently is what unupgraded Admin Deploy targets. In either case, this combo isn't guaranteed to happen in the first draw of your deck - you need to draw the retaining card before you draw the non-retaining one (or if Admin Deploy B is the retaining card, drawing it in the same hand as its target works too, which makes it a bit more reliable than putting Retain on the target). So you'll need to be OK with occasionally getting a slow start in combats if you're relying on this.
Admin Deploy + expensive card isn't the only combo you can make more reliable with this - Overclock and a card that applies a powerful Status, like I Frames or Power Play is another example. You can also make Math.Max retain, seeing as it's a powerful combo ingredient - in particular, if you're looking for an infinite combo, you often want to wait to use it until you've Exhausted enough other cards. This will make Total Cache Wipe awkward if you have that - note that you can use this to de facto upgrade Total Cache Wipe to its B version without increasing its Energy cost.
If you later find Lightspeed Boot Disk, you can apply that to the same target this is applied to in order to make your desired combo fully guaranteed to line up on your first cycle through the deck, allowing you to rely on that combo and not need to worry about a contingency plan.