Zephr, Welcome!
My personal opinion after spending 8 years in California as an Environmental Compliance Manager in the construction industry and dealing with this stuff daily, is that Prop 65 has become a joke, which is unfortunate. It is supposed to be tool to identify risk, but so many companies are placing the label on their products as a CYA to provide a degree of separation of liability it means next to nothing now. I would recommend that instead of looking for something that doesn't have a Prop 65 warning on it, find a good freezer and research what's in it and why it has Prop 65 warning. Chances are it's the refrigerant. If exposed, COULD it possibly, maybe, someday, under certain circumstance cause cancer or a birth defect? If
the answer is anything but an emphatic no then it gets a Prop 65 label. You aren't going to be exposed to the refrigerant unless you go and cut open the lines, so the risk is extremely low.
Freezers are made from sheet metal, paint, some plastics, copper and steel tubing, a compressor that will have copper in it, an insulation, and a refrigerant. There are some other bits in there like a thermostat and relays that could have lead contacts or possibly mercury. Prop 65. The insulation would be my biggest question. Off gassing of whatever is in that would be the only real risk.
That's my 2 cents on it.