Which of these droids would be the best as an assassin?

YVH, IG, or BX.

The rest serve are security personnel and wouldn't work well in a assassin type role.

IG-88 was literally immortal.

Didn't see IG somehow but I change my vote.

Literally the only assassin here is IG 88.

It's between Third Generation Dark Trooper and IG-88

IG 88 would easily be the best assassin out of all these choices but, if you are talking about the IG droid series I would say the Dark Troopers are the obvious choice.

A dark trooper isn’t stronger than a Magnaguard though

They are bro trust me 💀

I’ve seen them in action before lol Magnaguards are a challenge for Jedi, dark troopers would be sliced through like butter

Stronger doesn't mean more skilled, it would make sense for a dark trooper to be PHYSICALLY stronger and not be SKILLFULLY stronger. Plus Magnaguards aren't exactly challenges, their tech just allows them to be decapitated and still fight which isn't really a feat, Sovereign Protectors and Shadow Guards could honestly smoke Magnaguards.

Even then, assassinations are different from facing Jedi unless they're a high value target.