This is a simple brute force using JavaScript
You can try this script with Chrome DevTools/JavaScript Console
The Default Charset is "0123456789abcdefghijklmnopqrstuvwxyz"(Base 36)
in this example we set min string length to 4 (start from 'aaaa') and max string length to 6 (until 'zzzzzz')
Simply copy and paste this script into JavaScript Console:
for(i=parseInt("aaaa", 36);i++<=parseInt("zzzzzz", 36);console.log(i.toString(36)));