Just a few examples. We do not claim to know of every potential danger.
Please always do your own research on safety for your pets.
Please use your discretion when reading this page if children are present.
BAGS! Many bags are suffocation hazards to pets. A few examples include potato chip bags, pet food bags, treat bags, and plastic bags. There's even anecdotal evidence that pet food and other cans may also be risks.
XYLITOL! This ingredient is found in many household items, including many peanut butters and other food items, toothpaste, and chewing gum. It's used as sweetener for human items but is very poisonous to dogs even in small amounts.
SUGAR! Sugars in foods can tend to over-rev dogs and of course are not the best thing for them. If your dog has trouble paying attention or being calm during training, for example, check the ingredients list of the foods/treats you're using.
OXYGEN ABSORBERS! These are tiny packets of elemental iron granules placed in the packaging of certain human and pet foods/treats. Elemental iron is extremely toxic even in small amounts.
CHOCOLATE & OTHER CANDY! Chocolate is especially toxic to dogs, even in tiny amounts, and candy-eating can lead to pancreatitis, which is painful and sometimes fatal.
GRAPES & RAISINS! Extremely poisonous to dogs, PetPoisonHelpine (link below) says that any ingestion of these items should be treated as a poisoning. Some other human foods, such as garlic, can be toxic to pets as well.
CHEWABLES! Many items given to dogs for chewing or 'dental cleaning' pose potential hazards. For example, bully sticks can be choking hazards, especially as they are chewed down. A dog might chew off pieces of rubber or plastic 'bones' and swallow them, risking a blockage/injury, while some real bones (and other hard chew items) can splinter or crack teeth if a dog tries to bite instead of chew the item. Certain shaped bones and toys may go over the front teeth and become stuck on a dog's jaw. Additionally, if a chew ball only has one hole, it may be a suction risk.
LASER POINTERS, GLOW STICKS, ROPE, TENNIS & OTHER BALLS: Some dogs are so intense with their toys that one might argue any toy can be a risk. If your dog shreds or dissects and eats parts of toys or the squeakers etc inside them, this is a valid concern. Other potential hazards are ropey items, as the strings can be swallowed and cause internal harm, glow sticks, which dogs may mistake for chew sticks, and even tennis and other balls, which have occasionally become lodged in a dog's throat. Laser pointers have been associated with development of compulsive disorders as well as overmuch interest in chasing, not to mention the fact that the poor dog can never 'catch' a laser beam, which can lead to frustration or other issues, reducing welfare.
VEHICLE TRAVEL ITEMS! Did you know that many crates and other items commonly used for pets riding in vehicles may not be safe? To learn more, check out some crash tests and reports here: https://www.centerforpetsafety.org/test-results/harnesses/cps-approved-harnesses/ and here: https://www.centerforpetsafety.org/test-results/
GARDENS! In addition to many mushrooms, myriad plants, trees, leaves, berries, petals, and flowers are poisonous to dogs. Fertilizers, snail pellets, and other pest killers are typically poisonous to dogs as well. It's not all bad news about gardens; though! You can create wonderful sensory gardens for your dogs by selecting a variety of non-toxic, non-injurious plants that offer a variety of aromas, textures, and so on, and planting them in interesting patterns, heights, and paths for your best friend! If you're not sure what's toxic, you'll want to check several reputable pet safety sources online, and possibly even consult with botany professionals.
REMEMBER: This is just a partial list. Always implement due diligence. For example, read product reviews for owner reports of dangerous experiences with dog items, and read poisonous items lists; here's one: https://www.petpoisonhelpline.com/pet-owners/
Finally, even if you decide the item is safe, always directly supervise when in use.