You have a lot of options because 18GB is sort of large but not large enough to raise eyebrows at the “unlimited” providers.
Years ago, one of my family members had a 35GB static site that I was rotating through intro offers at the largest providers like BlueHost, HostGator, and DreamHost. None of them had any issues.
You could go with one of the lifetime offers that @Miguel posted here: MyW - IT'S MY BIRTHDAY - LIFETIME OFFERS! Shared/Reseller Hosting, DE, LA and SG!