Kruskal's Algorithm - Sort arcs into ascending weight, then pick the arcs in order, remove any that make a cycle, continue adding until all vertices are connected
Prims Algorithm - Choose any vertex to start the tree, select the arcs of least weight, carry on doing this until all edges are connected and there are no cycles
Dijkstra'sAlgorithm - Finds shortestpath between any2vertices, you can use Dijkstra's on a digraph
Floyd's Algorithm - Finds shortest paths between every pair of vertices in a network