Viator:

Use them to book tours in any location. Not just the US, but any location in the world. I use them on every single trip I go on. From a 2-3 walking tour, all-day tour of a city, multi-day tour of a region, they have it all. Not only that, but the type of tours vary too. They offer historical tours, hiking tours, ghost tours, food tours, and many more.

VRBO:

Use them to book your vacation rental. Not just in the US, but across the world. I book through them often and have always had a positive experience. If you do have any issues their customer service is usually excellent. They don’t rent out shared spaces, only stand-alone ones. You’ll find homes, apartments, condos, and more on there.