is it allowed to sell “Teamspeak Server Groups” for real money? Or is there an EULA that prohibits this?
Only when it’s not a non-profit/sponsored-by-teamspeak server. You can see this, when you check the server license.
So… servers with the…
- Non-Profit License
- Sponsorship License
… are not allowed to sell anything or accept donations.
As far you have another (or none) license, then you can.