19 years later couples

Harry/Ginny
Ron/Hermione
Draco/Astoria Greengrass
Neville/Hannah Abott
Luna Lovegood/Rolf Scammander
George Weasley/Angelina Johnston
Percy/Audrey(don't know her last name)
And I also like to believe that Snape and Lily Potter end up together in heaven(:

Harry & Ginny
I'm sure anda knew about this couple. Harry and Ginny had three kids. Their oldest was James Sirius Potter, the middle child being Albus Severus Potter, and the youngest was Lily Luna Potter. Because of Lily's middle name, we can guess that Ginny and Harry kept in touch with Luna Lovegood.
Ron & Hermione
This was probably the most obvious couple. Ron and Hermione had two kids, a girl named Rose Weasley, who, during the epilogue of the last book, was going to be starting her first tahun at Hogwarts, and a boy named Hugo Weasley who was too young to go to Hogwarts during the epilogue. Rose Weasley, according to Ron, has inherited her mother's brains.
Draco & Astoria Greengrass
Astoria Greengrass was the younger sister of Daphne Greengrass, who was in Draco's tahun at Hogwarts. They had one child named Scorpius.
Neville & Hannah Abott
Neville married Hannah Abott, who was a Hufflepuff in his tahun at Hogwarts. They lived at the Leaky Cauldron, where Hannah became the landlady.
Luna & Rolf Scammander
Rolf was a magical creature hunter than Luna met on her expeditions.
George & Angelina Johnson
Somehow not surprising.
Percy & Audrey

Harry Potter/Ginny Weasley
Ron Weasley/Hermione Granger
Neville Longbottom/Hannah Abbott
Luna Lovegood/Rolf Scamander
George Weasley/Angelina Johnson
Percy Weasley/Audrey (unknown surname)
Draco Malfoy/ Astoria Greengrass

Harry Potter and Ginny Weasly
Ron Weasly and Hermione Granger
George Weasly and Angelina Johnson
Neville Longbottom and Hannah Abbot

Rose Weasley and Scorpius Malfoy