* Close friends might exchange small, meaningful gifts: This is more about personal relationships than a widespread expectation. Think small tokens of friendship, not expensive presents.
* Class gifts: Sometimes a graduating class will pool money together to buy a gift for the school, a teacher, or another collective entity. This is organized by a committee, not individual students giving gifts to one another.
* Yearbook signings: While not strictly gifts, personalized messages and signatures in yearbooks serve a similar purpose of commemorating the shared experience.
In short, while some personal gift-giving might occur between close friends, there's no general expectation or tradition of high school graduates exchanging gifts amongst the larger graduating class.