A cli vanity generator
yarn run:vanity --match cook13 --mnemonic --network kusama --type ed25519
When using the --mnemonic option, the generation will be very slow since it needs to generate mnemonics and then test the resulting outputs.
As with all other cli utilities --help will return a list of the available options.
If you are installing it globally -
$ yarn global add @polkadot/vanitygen
$ polkadot-js-vanitygen ...