Based on the search results, here are some of the worst nail art products, along with their details, positive and negative aspects, and ingredients or materials:

1. Nail polishes with toxic ingredients: Many conventional nail polishes contain harmful chemicals like toluene, formaldehyde, and dibutyl phthalate, which are linked to chronic diseases and cancers. Some nail polishes may also contain aluminum powder, which is moderately hazardous. These chemicals can be harmful to both nail technicians and customers, causing allergies, asthma, and dermatitis. However, there are many non-toxic nail polish brands available that are formulated without these harmful ingredients.

2. Nail wraps with questionable ingredients: Some nail wraps may contain harmful ingredients like formaldehyde and phthalates, which can cause damage to wearers. However, there are brands like Polish Pops that offer completely safe nail wraps made from all-natural ingredients.

3. Polygel kits with MMA: Some polygel kits may contain Methyl Methacrylate (MMA), which is a harmful substance that can cause blisters, skin peeling, itching, and burning. It is important to be cautious when buying any nail products and to do research to make sure you know what you’re buying.

In summary, it is important to be aware of the ingredients and materials used in nail art products to avoid harmful chemicals and substances. There are many non-toxic nail polish brands and safe nail wraps available that are made from all-natural ingredients. It is also important to buy from reputable companies and to do research before purchasing any nail art products.