"....the rosette on Harry’s chest kept squeaking their names: 'Troy - Mullet - Moran!'"
-- Irish National Team souvenir at the 1994 Quidditch World Cup (GF8)
Enchanted colourful badges of ribbon, worn to show support for your Quidditch team. They shout the names of the players until the charm wears off during the next day or so (GF7, GF8).
Ron, Charlie, Bill and Ginny Weasley and Harry Potter all bought Ireland National Team rosettes at the 1994 Quidditch World Cup (GF7, GF8).
Seamus Finnegan had also bought one, which was still weakly saying the names of the players on the train to Hogwarts. He eventually pinned it up next to his bed (GF11, GF12).
Notes and interesting facts:
- Non-magical rosettes were also worn by students (and Hagrid) to support their House Quidditch team at Hogwarts (PA15, OP19, HBP4).