Pay attention to folding toys (such as little push-chairs for dolls or small iron tables), which are dangerous for children's fingers, as well as toys with visible mechanic parts (e.g. springs, cog-wheels, etc) which can cut kids' fingers or get caught in their hair.
Also pay attention to shooting toys (airguns, etc) because they might cause serious injury, especially to the eyes.
Toys that contain laces, ropes, straps or belts are also dangerous and require supervision, because they might easily get wrapped around your kid. Additionally, make sure that the kids do not touch toys' batteries because they are toxic.
Finally, lay emphasis on your children's pastime with video games, which, mainly, are of violent content. Many hours lasting use of video games might result in communication and behavior problems as well as increased nervousness.