[avereveard]

https://store.steampowered.com/app/2410820/Too_Many_Sheep/ both cooperative and competitive

[SrZorro]

Also, https://store.steampowered.com/app/3006280/Sheepherds/

> A cozy co-op party game where you and your sheepdog buddies guide colorful flocks through beautiful landscapes [...]

It has a free demo but no release date yet