Possibly something like Verses Mode

This mode would focus on which player can survive the longest. The players would start out with nothing, and just like survival mode, must gather as many materials as they can in 1-5 minutes (game creator can decide). Once that time is up, they must survive a wave. of zombies. Once the wave is defeated, the last zombie drops a piece of armor (initially a leather armor piece). The next round would have another piece of the armor set and so forth until the set is complete, then a special round starts. They have 1 minute to collect any materials they need. After time runs out, they have a chance to earn a better tool or piece of armor. From then on, special rounds happen every 5 waves.

The first wave would start with 15 zombies and go up by 10 each wave. There could also be a free for all where players spawn with a sword and compete to see who can kill the most enemies in a certain amount of time.