As a side effect, these also typically extend the length of Commander/EDH games by 20 minutes
Kaladesh, like most artifact sets before it, was pushed to the limit as far as power level was concerned, which led to multiple bannings in Standard (and was around the start of bannings being so in vogue in Standard)
The big news right now is Overlord of the Balemurk, which quickly spiked from $12 to over $30 after Joel Doolittle made Top 8 at the SCG Con Portland Regional Championship with a (mostly) fair-looking Orzhov Ephemerate deck
I've placed a focus on haymakers that provide immediate or near-immediate value the moment they're cheated into play, so either combat damage (Demon of Loathing) or ETB (Lord of Change) or end step (Brainstealer Dragon)
All in all, I expect [casthaven]Malfunction[/casthaven] to be a comparably bad-but-powerful removal spell much like Sleep Paralysis was
Urtet, Remnant of Memnarch Urtet, Remnant of Memnarch is a nice 5-color Myr commander