Timsort with its time complexity of O(nlogn) in the worst case and O(n) in the best case, has become the default sorting algorithm for Python, Java, and other programming languages.

Treap is an efficient and simple data structure that combines the best of both binary search trees and heaps. It provides the benefits of efficient search, insert, and delete operations.

Regex is efficient because most programming languages implement optimized regex engines that handle pattern matching using sophisticated algorithms like finite automata, ensuring fast performance.

NLTK (Natural Language Toolkit) is a powerful library in Python that provides easy-to-use interfaces to over 50 corpora and lexical resources, including WordNet.