* Social Media: This is probably your best bet. Search for them on Facebook, Instagram, Twitter, LinkedIn (if they're older), and other platforms using their name, hometown, and maybe the name of your middle school. You might also try looking at mutual friends' friends lists.
* Middle School Yearbook: If you have access to your middle school yearbook (either a physical copy or a digital version if your school has one online), you can find their information there.
* Classmates.com or similar websites: Websites like Classmates.com are dedicated to connecting people with former classmates. You can search by school and year.
* Your Middle School's Alumni Association (if they have one): Some middle schools, especially larger ones, have alumni associations that might have contact information or ways to reach out to former students.
* People you still know from middle school: Ask friends you're still in touch with if they know how to contact this person.
* Reverse image search: If you have a picture of the person, you can try a reverse image search on Google Images or TinEye to see if it turns up anywhere online.
Remember to be respectful and understand that the person might not want to be contacted after all these years. Start with a friendly message explaining who you are and how you remember them.