There’s a wide variety of products you could sell in a comic or game store!
With comics or card games, they also have regular releases to the product line. While these stores might not have a huge customer count, there should be a very regular audience.
Cheap to make, cheap to sell, regular releases keep customers coming back
More expensive to create and sell, a pretty standard product
Cheap to make, can be priced a bit more aggressively. These could have regular releases or events hosted in store, adding hosting groups or game nights in addition to just selling products