It's generally not recommended to feed your pets anything other than their own food, because even if it's not poisonous, the food could cause health problems. For instance, dogs and cats can get diabetes from consuming too much sugar too.
Furthermore, when it comes to fruits, the fruit itself may be fine, but other things associated with the fruit are not. For example, apples are not poisonous, but their seeds contain a form of cyanide. This is true for a great many fruits, and so you must be careful to remove all seeds before giving it to your dog. There are also fruits where the unripened fruit is poisonous, or the plant that grows the fruit is poisonous, like the tomato. Or the peels or shells could even be bad for the digestive tract even if they are not technically poisonous.
A non-comprehensive list of common poisonous fruits:
- grapes and raisins
- tomatoes (while the perfectly ripe fruit is technically okay, you can't really be sure all the toxins are gone, so better not risk it)