A prime example is the 2019 War of the Spark set, which featured 36 alternate-art Japanese planeswalkers illustrated by renowned Japanese artists
The spike is largely due to its synergy with Sephiroth, Fabled SOLDIER, where the hordes of temporary Zombie tokens it produces create a cascade of death triggerspotentially enough to wipe the entire table in a single turn cycle
For example, if a player who controls Alhammarrets Archive would gain 3 life while Tainted Remedy is on the battlefield, that player may choose to have the 3 life become doubled to 6 life and then lose 6 life
For these cards, its important to choose sleeves with a clear back or sleeves specifically designed for double-sided use to ensure both sides remain visible and protected
In deciding which cards to put on the bottom and which ones to keep, my main strategy thus far has been to assemble an "ink curve"
I really don't like these items that are single use though