What are some impactful commanders that FEEL like true commanders/legends?

I'm not talking about value engines in the command zone. I'm not talking about small mana dorks or combo pieces. I'm talking about huge decently-costed creatures that have a real impact on the game the turn they come down and have a "raid boss" feel to them. Something that truly seems like a legendary creature and/or monster, not generic soldier #782.

What are some bad ass commanders like this?