Its an important distinction to make, because if a mechanic is not inherently broken in all cases (and very few are) then you can make the case for a new set figuring out how to implement them in a way which avoids the pitfalls of previous overpowered designs
We actually wrote a whole Commander Deck Tech about Karumonix, though, which will make his value far more clear than a single blurb could manage, so check it out if youre interested
Aside from Krydle and Volo, which Ive already done deck techs on, you can build a forced combat deck with Karazikar, the Eye Tyrant
Upon entering the battlefield through its ninjutsu effect, Thousand-Faced Shadow creates a tapped and attacking copy of another attacking creature
Scion of Oona At worst, this is a fairly standard lord with a slight downside (hexproof would be a vast improvement over shroud), but at best, this is the card that can mean the difference between every creature you control getting themselves killed, or doing the killing themselves