Some of my favorite villains growing up.
These villains, in my opinion, were fierce, intimidating, cunning, and unique in their own respective ways. within their universes, they felt like the embodiment of what an antagonist ought to have been, and all while maintaining some air of believability. In addition, the characters were believable, with concrete, reasonable goals for their ability level. Their fight scenes, their fluidity, the voice acting, and the ambience behind them, all came together to make these characters the terrors we know and love. Above all else, and this is what I most appreciate about them, is that they managed to avoid being worn out.
To this day, the mere mention of Slade's name strikes me with nostalgia from back when he haunted and nearly beat Robin to death.