When the war ended, the dementor's were rounded up by the Ministry and left to decay as nothing is really immortal despite the dementor's inability to die.

House-elves were also given more privileges and rights; like the right to pay and sick leaves etc. etc. I think that these rights were majorly influenced my Hermione who also wanted Goblins to be treated equally. After all this, all tensions between gobins, house-elves and wizards were eliminated and laws were set into place to prevent mistreatment to any creature.