@Fiona917 I provide several different types of ground coffee, including decaf, as well as a variety of teas, long-life creamers, sugar, honey, etc.
I also provide basic cooking ingredients like oil and spices, as well as non-stick cooking spray.
Unlike some others, I don't feel the need to lavish guests with gifts. The guests and I have a business agreement, and I have fulfilled my part by delivering my property as promised.
Good hospitality covers the basics: a property that's clean, comfortable, all things functioning, and all amenities in place.
I'm not going to spend my profit on gifts for people I don't know, and don't necessarily care about.
I do do things for repeat guests, as generally we have become friendly and genuinely like each other, but that's by choice, not because I feel some obligation.
You'll work out your own system and preferences, but you should not feel the need to buy and stock many of the things mentioned by other responders here.
The thing about instant coffee? That guy could have brought his own. It's really, really easy to transport and hardly weighs anything.