Product Hunting Failure

I have searched for products a lot but I just can’t find a product or how to check if a product would make sales or not.
I have narrowed down my list to some items, can you guys help me and tell me which of these have high demand but low supply and maybe you guys can share some products with me too,
1. Wireless headphones: There are hundreds of suppliers that sell those wireless headphones with charging box, in my opinion those might sell on amazon. that is why i need to know what you guys think.
2. Water Bottles: I think they might be in demand.

3.Pet Supplies.

These are the things i think would be worth selling, please share your knowledge on if that’s a good idea or not.