systemed

(Dijkstra and plain A* are generally not included here as there are thousands of 
implementations, though I've made an exception for rare Ruby and Crystal versions,
and for Thor, Mapzen's enhanced A*. )

A*                                      Ruby    https://github.com/georgian-se/shortest-path
A*                                      Crystal https://github.com/petoem/a-star.cr
A* (bidirectional with shortcuts)       C++     https://github.com/valhalla/valhalla
NBA*                                    JS      https://github.com/anvaka/ngraph.path
NBA*                                    Java    https://github.com/coderodde/GraphSearchPal
NBA*                                    Java    https://github.com/coderodde/FunkyPathfinding