Anterior Tibalis

I havent heard anyone mentioning about this yet. Is it also one of the muscles that you have to focus on during weight training? Or is it already worked out when you run/ plyometrics?

Exactly right, same for calf muscle.

Oni you can do something as simple as heal walks to help activate the tibialis.
If you are using hill running they will also work those muscles. If the tibialis is weak it can inhibit your ability to mantain poper running mechanics.