He had a few – let’s call it ‘curious’ – judgement issues (like that time he sent a jinxed Bludger after Harry during a Quidditch match), but he always meant well. Dobby initially served the Malfoy family but was set free when Harry tricked Lucius Malfoy into giving him a sock. ’Dobby has no master… Dobby is a free elf,’ he told Bellatrix, shortly before his demise in Harry Potter and the Deathly Hallows.
Harry met Winky during the Quidditch World Cup when he mistook her for Dobby. She was a sweet house-elf, but struggled with the idea of freedom, telling Harry that Dobby’s freedom was going to his head: ‘House-elves is not supposed to have fun, Harry Potter,’ said Winky firmly, from behind her hands. ‘House-elves does what they is told.’
She served Barty Crouch until she was dismissed. She thought that getting paid was a lowly idea, even when Dobby helped her secure a new job at Hogwarts. She eventually fell into a state of depression, seeking solace in too much Butterbeer, poor thing.
J.K. Rowling revealed during a webchat in 2007 that Winky fought against the Death Eaters during the Battle of Hogwarts.
Kreacher was first introduced to Harry at number twelve, Grimmauld Place, Headquarters of the Order of the Phoenix. He was house-elf to the Black family, and was left to Harry after Sirius’s death. Despite his disrespect of Muggle-born wizards, he still earnt the respect of Hermione Granger, who became an activist for house-elves through her organisation S.P.E.W. (Society for the Promotion of Elfish Welfare).
Kreacher, albeit against his wishes, did help Harry, Hermione and Ron when they needed to find out more information about Regulus Black’s locket, a prime piece of the Horcrux puzzle. However, they did see Kreacher again, leading house-elves in the Battle of Hogwarts.
Harry never actually met Hokey, but went inside her memories in the Pensieve with Dumbledore. She served Hepzibah Smith until being convicted by the Ministry of poisoning her mistress. The memory Harry witnessed was one of Voldemort’s visits to Hepzibah, where he altered Hokey’s memory after having the house-elf slip the poison into her cocoa.
It wasn’t until later, when Hokey was convicted, that Hepzibah’s family realised what was missing after Tom Riddle’s visit: Helga Hufflepuff’s Cup and Salazar Slytherin’s locket, both items the Dark Lord went on to use as Horcruxes.
Countless house-elves served in the halls of Hogwarts, cleaning, cooking and delivering trunks, among other tasks. Hermione disrupted the regularity with her S.P.E.W. activism but, like those she was trying to help, she certainly meant well. The last we saw of the house-elves in the story, they were mingling with others after the Battle of Hogwarts.
McGonagall had replaced the house tables, but nobody was sitting according to house any more: all were jumbled together, teachers and pupils, ghosts and parents, centaurs and house-elves, and Firenze lay recovering in a corner, and Grawp peered in through a smashed window, and people were throwing food into his laughing mouth.
Harry Potter and the Deathly Hallows