Hi!
Omg thank you so much for buying the bonus pack.
The .gb roms are always free. You can get them in the game’s folder on steam, download them on itch, or get them off my personal website located here:
https://taylormccue.neocities.org/
You can buy the bonus pack on this itch page or on steam directly here:
https://store.steampowered.com/app/2447770/HFTGOOM__BONUS_PACK/
(I think reading this you already own it on itch. Let me know if you need help figuring out how to redeem the steam key.)