When it comes to using utensils on a cast iron skillet, there are really only two options that you need to concern yourself with: wooden or metal. Which one you use is really up to personal preference, but each has its own set of benefits and drawbacks that you should be aware of.
If you opt for wooden utensils, the main benefit is that they won't scratch the surface of your skillet. This is important because any scratches on the surface can potentially lead to rusting down the line. However, wood is a porous material, which means that it can absorb some of the oils and flavors from whatever it comes into contact with. This isn't necessarily a bad thing, but it's something to keep in mind if you're particularly concerned about keeping your cast iron skillet in pristine condition.
Metal utensils, on the other hand, won't absorb any flavors or oils, but they runs the risk of scratching the surface of your skillet (although this is less likely to happen if you're using stainless steel). If you do end up scratching your cast iron skillet, don't worry – as long as you season it regularly, the scratches shouldn't affect its performance or longevity.