If you are a beginner to medium level, follow this order (Standard Base🔥):

Q1: Binary Tree Level Order Traversal - (LeetCode 102)
Q2: Average of Levels in Binary Tree - (LeetCode 637)
Q3: Level Order Successor of a Node - Google
Q4: Binary Tree Zigzag Level Order Traversal - (LeetCode 103)
Q5: Binary Tree Level Order Traversal II - (LeetCode 107)
Q6: Populating Next Right Pointers in Each Node - (LeetCode 116) - Amazon, London
Q7: Binary Tree Right Side View - (LeetCode 199) - Amazon, Flipkart
Q8: Cousins in Binary Tree - (LeetCode 993)
Q9: Symmetric Tree -(LeetCode 101) - Amazon, Google, Apple
Q10: Diameter of Binary Tree - (LeetCode 543) - Google, Amazon, Facebook
Q11: Invert Binary Tree - (LeetCode 226) - Google (Many Times)
Q12: Maximum Depth of Binary Tree - (LeetCode 104) - Google
Q13: Convert Sorted Array to Binary Search Tree - (LeetCode 108)
Q14: Flatten Binary Tree to Linked List - (LeetCode 114) - Facebook
Q15: Validate Binary Search Tree - (LeetCode 98) - Amazon, Google
Q16: Lowest Common Ancestor of a Binary Tree - (LeetCode 236) - Amazon
Q17: Kth Smallest Element in a BST - (LeetCode 230) - Facebook, Amazon, Google
Q18: Construct Binary Tree from Preorder and Inorder Traversal - (LeetCode 105) - Amazon (Many Times)
Q19: Serialize and Deserialize Binary Tree - (LeetCode 297) - Google, Facebook, Amazon
Q20: Path Sum - (LeetCode 112) - Amazon
Q21: Sum Root to Leaf Numbers - (LeetCode 129) - Microsoft, Apple, Google
Q22: Binary Tree Maximum Path Sum - LeetCode 124) - Facebook
Q23: Path Exists in Binary Tree from Root to Leaf
Q24: Path Exists in Binary Tree at Any Nodes (here not only from root to leaf node it may be any like Leaf to Leaf also...path kind of largest..etc).
Q25:DFS Using Stack Implementation

If you want to test your problem-solving skills🚀💯🔥:

More than 2 companies asked questions (decreasing order):
Q7: Binary Tree Right Side View - LC 199 - Amazon, Flipkart
Q9: Symmetric Tree - LC 101 - Amazon, Google, Apple
Q10: Diameter of Binary Tree - LC 543 - Google, Amazon, Facebook
Q17: Kth Smallest Element in a BST - LC 230 - Facebook, Amazon, Google
Q19: Serialize and Deserialize Binary Tree - LC 297 - Google, Facebook, Amazon
Q21: Sum Root to Leaf Numbers - LC 129 - Microsoft, Apple, Google

Q15: Validate Binary Search Tree - LC 98 - Amazon, Google
Q18: Construct Binary Tree from Preorder and Inorder Traversal - LC 105 - Amazon (Many Times)
Q11: Invert Binary Tree - LC 226 - Google (Many Times)

Amazon-specific order (test yourself here):

Q18: Construct Binary Tree from Preorder and Inorder Traversal - LC 105 - Amazon (Many Times)
Q6: Populating Next Right Pointers in Each Node - LC 116 - Amazon, London
Q7: Binary Tree Right Side View - LC 199 - Amazon, Flipkart
Q9: Symmetric Tree - LC 101 - Amazon, Google, Apple
Q10: Diameter of Binary Tree - LC 543 - Google, Amazon, Facebook
Q15: Validate Binary Search Tree - LC 98 - Amazon, Google
Q16: Lowest Common Ancestor of a Binary Tree - LC 236 - Amazon
Q17: Kth Smallest Element in a BST - LC 230 - Facebook, Amazon, Google
Q19: Serialize and Deserialize Binary Tree - LC 297 - Google, Facebook, Amazon
Q20: Path Sum - LC 112 - Amazon

Google-specific order (test yourself here):

Q11: Invert Binary Tree - LC 226 - Google (Many Times)
Q3: Level Order Successor of a Node - Google
Q9: Symmetric Tree - LC 101 - Amazon, Google, Apple
Q10: Diameter of Binary Tree - LC 543 - Google, Amazon, Facebook
Q12: Maximum Depth of Binary Tree - LC 104 - Google
Q15: Validate Binary Search Tree - LC 98 - Amazon, Google
Q17: Kth Smallest Element in a BST - LC 230 - Facebook, Amazon, Google
Q19: Serialize and Deserialize Binary Tree - LC 297 - Google, Facebook, Amazon
Q21: Sum Root to Leaf Numbers - LC 129 - Microsoft, Apple, Google

Edited:
FaceBook Specific(test yourself here):
Q1, Q4, Q6, Q12, Q13, Q16, Q18, Q21