What to bring to the adoption??

Hey there! I've been creeping on this sub for a few months while I prep for the big adoption day, and it's finally around the corner! The only question I haven't found an answer to is if there are any suggestions for what to bring to the adoption?
I am planning on going to a shelter, but I find the website FAQs don't have all my answers either.

Should I purchase a carrier beforehand and bring it, or will they give me something to take my new friend home in? Should I bring a blanket? Treats?

Any day-of adoption suggestions and tips would be greatly appreciated, thanks!