Note: This index is not exhaustive.
Trie
Suffix Array
Suffix Automaton
KMP
Segment Tree
Segment Tree + Lazy Propagation
BIT (Fenwick Tree)
Merge Sort Tree
2D Segment Tree
Radial Sweep (and Polar Sort)
Convex Hull
Sweep Line
Minkowski Sum
Quadrilaterals
Segment to Segment Distance
Circle & Segment Intersection
Tangents & Arcs
Polygon Tangents
Geometry with Dynamic Programming
Convex Polygons + Two-Pointers
Concave Polygons
Point Inside Polygon
Polygon Intersection
Half-Planes Intersection (Finite Area)
Rectangle-Rectangle Intersection
Simple Polygon Detection
Misc
BFS, DFS
Bipartite Matching, Max Flow, Min-Cut
Minimum Cost Flow
Dijkstra
Bellman-Ford
Topological Sort
Minimum Dominating Set
Hungarian Algorithm for Assignment Problem
Counting, Combinatorics, Math
Maximization, Minimization
Probability
Binary Search
Ternary Search
Tree Problems
Cycle Detection
Fast Fourier Transform
Union Find (+ Minimum Spanning Tree)
Sparse Table
Prefix Sum
Lowest Common Ancestor
Coordinate (or Arrays in General) Compression
Rope
Ordered Set
Fast Exponentiation, Fast Fibonacci, Etc
Modular Division
Simpson's Integration
Kadane's Algorithm (Maximum Subarray Problem)