Falling hazards: stairs are certainly at the top of the list for potential hazards. However, even one step from one level to another, if taken the wrong way, can bring disaster.
Chemicals: it’s important to store all chemicals high out of reach of small children. More than that, it would be good to lock them up, since children love to climb.
Water: pools are of course very dangerous if children are left unsupervised. However, you may also consider other areas of your home where standing water could cause harm.