Sterlingdf:
I have found that clothing stores that carry the XLB sizing for men are the best fit for my big belly shape. Here is more info on the XB sizing.
In clothing, XLB stands for Extra-Large Big, referring to a size with extra width for a larger frame but a standard length. XLT, on the other hand, stands for Extra-Large Tall, indicating a size with extra length for a taller person.
The key difference between XLB and XLT is in their proportions.
XLB (Extra-Large Big)
Target build: Men with a larger and fuller body, such as a broader chest, thicker torso, and larger waist, but who are of average height.
Proportions: The clothing is wider across the chest and midsection than a standard extra-large (XL). The sleeves and body length, however, are cut to a typical extra-large length.
Best for: Individuals who need more room around the chest and stomach but don't need the added length that comes with "tall" sizing.
So, XB clothing is perfect for gainers like me. I have been shopping at Kohl's which carry some XB styles. If you find other XB stores, you should list them in this thread, please.
I've had great success at JC Pennies as well. But be warned that when it comes to pants, the biggest size I found was a 52 in waist. Thankfully, it was the perfect fit for my partner, but they weren't easy to find.