I have 2 in mind.
1. Nick Franco. Cheater, womanizer, big-time Playboy. Not caring about whose heart he stepped on to get there.
2. Edna from Swan Song. The way that she treated Tommy Brown was pure despicable.
I don't know if he really had it coming, but I wasn't upset when Jesse Jerome was killed. I'm not excusing what Santini was running from, but Jerome seemed like such a despicable person who only cared about the almighty dollar.
This is just my opinion but I feel like most blackmailers have it coming. Not the point the finger at anybody specific in the series but blackmailing is definitely a high motive for killing.
I would say Tony Galper in "Columbo Likes the Nightlife."
He wasn't just a bad guy, but his death was an accident while Vanessa was defending herself.
In the same episode, Linwood was also a despicable victim, but that was a cold-blooded murder, which makes it harder for me to say he "deserved" it.
I was seriously considering those two also quid.
Yeah, Edna got what she deserved!
I don't know about deserving it, but Karl Lessing really "asked for it."
Not only did he PRETEND he was willing to negotiate with Viveca, he also pretended that he wanted HER back.