Higher Kinded Types, yes, but implicits... Yuck. Scala has definitely proven them as a failed experiment, I hope we will never seem them again in languages going forward.
They are also quite useful for wiring up context (take Akka's ActorSystem, for example) at the declaration level, so that the bodies of your classes and functions only explicitly talk about your domain objects, rather than framework machinery.
They're also a big part of the power behind projects like Shapeless, which are quite useful for scrapping boilerplate.
Most controversially, they are also used to implement implicit type conversions. Modern idiomatic Scala discourages this, but it can sometimes be helpful.