Honestly, if the steak is really good, to me the only thing it needs is a dry rub, like a Santa Maria dry rub. Or simply salt, pepper, and garlic. And if I pan fry, I like coconut oil. But we can’t use butter; I hear it’s very good on steaks though!!
I agree with Yaelle. Sometimes going simple is best, especially with a good steak. Salt, pepper, and garlic is what I generally use. Having said that, there is nothing wrong with some good all-purpose steak seasoning, if you have it.