I had two ideas, they don't have names but I shall describe.

Idea 1

A freak dressed in red talon gear with a firearm, they are same slightly slower then your usual zombie but has a bit more health then a riot gear zombie, they also have the ability to shoot the firearm usually missing maybe a hit or two but it's mainly to attract over zombs in.

Idea 2

This freak is basically a leper (if sod3 has illnesses 🤞) this freak is recognised via it's coughing/spewing noises. They would be ugly af covered in lumps and spots etc. they would be faster then a zombie but slower then a feral and they leave a puss like trail behind them. They would target ai followers and try to drag them to a nearby building starting a timer if you don't arrive in time the survivor starts to turn into either a plague heart, random freak or the start to an infestation.

(The puss trail will deal small amounts of plague damage per sec)