I recently came across a python script which creates random characters like CRUNCH and cracking a WPA / WPA2 cap file.

This script can be found at  https://github.com/blmvxer/passgen/  provide a good GPU and you wont need a wordlist anymore.

 

Furthermore a custom list can be generated , Please see the example below

./crunch 8 8 -f /usr/share/crunch/charset.lst numeric -t ‘abc@’@@@@ -l abc@0000