What are the brands that sell 100% stainless steel cookware(interior and exterior)?!

You do not want 100% stainless steel cookware, because it's a poor conductor of heat. All high quality "stainless" cookware is layered with stainless steel only on the exterior and interior surfaces, while having at least an internal heat spreading core of aluminum or copper. Not all stainless steel is sufficiently ferrous (magnetic) to work with electric inductive cooktops, so some "stainless" cookware adds an additional layer of ferrous steel in addition to the thermal cores.

You also wouldn't want a slow cooker that's 100% stainless steel, because the uneven heating would cause food to burn more quickly. They are usually made of ceramic stoneware for a reason, even heating. Besides, a "stainless" pressure cooker (with alum/copper) core can in less than an hour everything a slow cooker does in 3+ hours, with better flavor, color, and nutritional content.

By the way, the Prestige "stainless" cookware isn't 100% stainless, of course, and that's a GOOD thing.

My SS pans are Prestige.