The Kg change plates from DHS are Awesome. They do have a bit of friction on them so they hold the bigger bumper plate weights on the bar decently. They are rubber coated and coloured. The set comes with 2-.5kg, 2-1kg, 2-1.5kg, 2-2kg, 2-2.5kg, 2-5kg plates. 1 have used them for over a year without any issues.
For a more economical set, you can check out Bells of Steel.