Murktide Regents Secret Lair promo, for example, is worth $2500 according to TCGplayer
Referring to a character costing N ink as an N-drop, the dream is to achieve a curve with a one-drop on turn one, a two-drop on turn two, a three-drop on turn three, and so on before running out of cards
They can be played alongside high-cost cards in order to spend your extra ink and develop your board, they can get buffed by a Support character like Rolly and become a cheap way to trade up into bigger threats, and Lucky can discover them when you use his ability Good as New, making them more valuable in your deck than in your hand
Thanks to our good friend Lier, you can make some nasty plays you can reduce the cost of Divide by Zero with Geistchanneler, and Lier will give it flashback and prevent your opponents from countering it
Items, however, can be used as soon as you play them
This is a less political option than the previous two entries, but feels a bit less risky than paying to load up someone elses hand