cdt2d
Constrained Delaunay Triangulation in 2D
poly2tri
A 2D constrained Delaunay triangulation library
pnltri
Polygon near-linear time triangulation (based on Seidel's algorithm) with ear clip for small cases. Handles degenerate cases of colinear edges and vertices touching edges.
path-of-least-regret
Lightweight 2D polygon navmesh pathfinding: triangulation + A* + funnel + smoothing.