Genya

if you like one you will definitely like the other both have female lead villains and an unusual type of plot

Sociopaths in love.
Murder, manipulation, naiveness, betrayal...
The ladies prevail!

Both shows weren't very well received but I personally think there's something so intriguing about just watching bad people be bad.

Questionable female leads, naive male leads.
In Genya's case, the female lead is the source of a lot of crime and killings, whereas in Ice World, the female lead is framed into looking just as bad.
There are over-passionate cops trying to take down the FLs in both as well.

Male leads murder a family member in the immediate aftermath of an earthquake.
There is mystery surrounding the leads/their past, and they're being followed/hunted by a cop/reporter.

Male lead of SNU & female lead of Genya both have secret pasts that they run/hide from. They've changed their identities and now have detectives hunting them for recent murders.
Female lead of SNU & male lead of Genya naively fall for them and help them cover up their crimes.