People who have never gotten an Otherworldly Bond before, who are you hoping to use it on?

The fact that we've gotten a free otherworld bond this year is absolutely crazy. I've never put any real thought into who I'd get cause I never thought I'd be able to even get someone off a binding worlds event, so now I have absolutely no clue who I'd use it on! I'm thinking Saber, since he's the oldest unit I have that I actually would like to invest in a bit, but I'd need to properly look through my barracks