A list of interesting creatures with their ups and downs that fit that standard:
Troll Ascetic
Witchstalker
Stillmoon Cavalier
Aven Mindcensor
Boon Satyr
Caller of the Claw
Wolfir Avenger
And some options that have similar utility, but aren't quite what you're looking for:
Restoration Angel
Thrun, The Last Troll
Kitchen Finks
Blade Splicer
I feel like if we go in this direction, we want to be the Rest in Peace deck against other BGx decks and things like TES. Then we want to be the Bolt-resistant deck against URx tempo. Witchstalker is intriguing to me. I keep forgetting it exists. It's sort of like Voice of Resurgence in that no one will ever play into it unless they don't care about the value you get, so it's essentially a City of Solitude or a huge alarm bell that something is about to happen. So if you can take that as a signal and then use hand disruption to get around it, that option is there for you.
Thrun just seems like a big-time house that's underplayed. I have been tinkering with a Junk deck featuring Time of Need and Doran in Modern and Thrun is so good there. We get GSZ in Legacy, but it takes 5 mana to get to Thrun. Hard to say what's better or worse but Thrun might be the answer we seek (and it's good under Deed)

