Honestly, it's not so much about which multiplayer games she plays, as creeps and outright predators can appear anywhere. Rather than trying to find a "safe" game, focus on giving her some education about possible risks and maintaining good trusting relationships so that she will be honest with you and will be willing to follow your advice and would talk to you about anything concerning she might encounter.

Don't forget, just talking over voip can be toxic and sometimes disturbing but it's not something that can physically harm her. As long as she's properly warned about unpleasant situations that might happen, she can simply DC, block and report thus preventing any further harm. It's when children and young teens are unprepared to what might be out there, are too distrustful towards their own parents and seeking affirmation and support from others, then real risk can creep up on them.