I typically use Restaurant Depot off of I 77 and Rockside Dr on Halle Drive for 7/11 tomatoes, GM Full strength Flour, cheeses and pepperoni . Any business license (Vendor's license) in Ohio will get you membership.
Alesci's Italian store on Mayfield Rd has 6 in 1 tomatoes in retail size cans and some other unique Italian items. Gallucci's Italian Market on Euclid Ave in Cleveland is the mecca of retail Italian stores in Cleveland and repackages many commercial items (pepperoni and cheese). Be sure to grab a cannoli for the ride home.
Crostatas Rustic Pizza on Bishop Road in Highland Heights will sell couple pound to full bags of 00 flour.
Sidari Italian Importers on Lakeside in Cleveland has a very small retail shop for olive oil, Calabrian Peppers, pasta and such. If you ask they will let you order from the wholesale section "in the back" but it will be in case lots.
The various GFS Marketplaces around town have other useful items for our trade/hobby.
My favorite meat market is Fligners in Lorain on Broadway. They claim the longest meat counter in America. I find their quality of pork and beef excellent and their prices outstandingly low. Do not go the first week of the month or you will be waiting a fair amount at the meat counter. Other times it is only 3 or 4 people deep. But one time there were 40 customers before me during the first week. I do not like their boneless chicken breasts, however their boneless thighs are great. Avoid their fish.
For fish go to Seven Seas on Lorain Ave in Cleveland.
For Chinese Tink Holl on east 36th street in Cleveland. For Mideastern you cannot beat West Town Village Market on west 117th Street. Frank is the owner and a great guy. Many times I have asked him for advice on the best product, and he has not hesitated to take something out of my cart and put in the proper item! His home made Kafta is the best! He also has a small hot lunch counter and small butcher shop. Great place for lamb and bulk grains, beans, flours and rice. Pretty good bulk olives, and as Frank says: "you have to watch all olive salesmen!" :-)
More than you asked for, but I got on a roll and thought I would share all my best sources in case anyone was looking for them in our area. Took about a year and a half to find these. Good luck!