Full Binary Tree
A full binary tree (sometimes referred to as a proper[15] or plane or strict binary tree)[16][17] is a tree in which every node has either 0 or 2 children.
A perfect binary tree
It is a binary tree in which all interior nodes have two children and all leaves have the same depth or same level
Complete Binary Tree
A complete binary tree is a binary tree where all levels of the tree are completely filled except possibly the last level, which is filled from left to right. In other words, all nodes must be as far left as possible. Complete binary trees are commonly used in heap data structures.