The biggest issue with every one of these websites: dogs are amazingly size-diverse. They range from a 4lb chihuahua to a 200+lb mastiff. If humans were similarly diverse, we would run from 60lb dwarfs to 3000+lb giants. Poisons are all about the dose, or at least the dose per mass of dog. A Hersey bar that might kill or at least cause suffering for the chihuahua will likely do absolutely nothing to the mastiff. Dogs are also very diverse in health and constitution, from very sensitive purebreds with allergies and strong reactions, to resilient mutts that shrug off most things. So trying to create a website of what is and isn't deadly to "dogs" in general is very difficult.

Maybe a website about poisons for house cats. They range from perhaps 5 to 20 lbs.