Install crunch and then generate a word list with the following command. The 8 8 tells crunch to generate combinations that have a minimum and maximum length of 8. All the numbers from 1-0 tells crunch to use these characters, -o writes to output file.

Change options if desired.

crunch 8 8 1234567890 -o 8numberchars.lst

Further reading. https://tools.kali.org/password-attacks/crunch