Tidy Plates, also does dot tracking. It's how I manage multiple dots unless we're talking bosses here.
For fights that have multiple bosses, Shadowed Unit Frames, offer a boss unit frames display, that I use and I only track my debuffs on them.
As Constie said, Raven or ForteXorcist can track them, and I've used both and Raven for a long long time to even do some crazy stuff, but I've never really liked how they both do multiple dot tracking and at no fault of the adddons, but due to the limitation of how wow allows you to track multiple units.
Remember also that you can focus a target, and with focus targets you can also see dots and that is my preferred way to track dots for two entities.