I am planning to visit my uncle who is living in the UK for my next holiday. Should I apply for a family visa or general visa?
First, check whether you need a visa at all. You haven't indicated your nationality, so presumably you have found that you need a visa.
According to Family visitor visa eligibility, an uncle is not one of the types of family members that would make you eligible for a family visa (it is generally only immediate family and direct ancestors or descendants). Therefore, you probably need to apply for a general visitor visa.