Personally, I always thought Nightwing had an interesting rouges gallery. An eclectic assortment of ne'er-do-well/degenerates such as:
Blockbuster (Roland Desmond)
Torque (Dudley Soames)
Double Dare (Aliki & Margot Marceau)
Lady Vic/Stallion/Brutale (Blockbuster's hired assassins)
Shrike (former friend of Dick Grayson, now hired-assassin with a grudge)
Nite-Wing (Tad Ryerstad)
and most recently, The Judge.