More cake toppers.
In a zombie apocalypse, the baseball bat is a good option. In fact, it is probably best to go with something you might have nearby (and no matter where the apocalypse starts, a bat shouldn't be too far away). Even if the apocalypse hits on your wedding day.
But most of all, you've probably held one before. That's the important thing. Go with something where you know the weight and how to swing it.
Here are a few couples who had that sensibility going.
Some of us might be more familiar with an acoustic guitar, which is just fine too.
And here's a pitcher who decided she could make a ball into a deadly weapon. Her groom picked up an less likely weapon to go along.