These are "beautiful" sonorous domain names in the new zones, which currently exist for about two hundred. Lists of premium domains are determined by the Registries of the corresponding domain zones. The cost of registering and renewing premium domains is higher than that of normal domains, and depends on the requirements of the specific Registry.
Check the cost of registering a premium domain through the name selection service on the nic.ru homepage. Premium domains are marked with a "premium" sign, by clicking on which you can see the price of the renewal.