There are LAWSON, 7-Eleven, and FamilyMart. (These three are major convenience store chains, but there are actually others as well.)
In Tokyo, there are 1,651 Lawson stores, 2,914 7-Eleven stores, and 2,400 FamilyMart stores (as of March 26, 2025).
With a total of 6,965 stores, you can rest assured.