Here is a list of common pathfinding algorithms, ordered from easiest to hardest:
Breadth-first search (BFS)
Depth-first search (DFS)
Dijkstra's algorithm
A* (A-star) algorithm
Bidirectional search
Bellman-Ford algorithm
Floyd-Warshall algorithm
Johnson's algorithm
It's worth noting that the difficulty of an algorithm can depend on the specific problem and implementation, so this list is a rough guide. Additionally, there are many other pathfinding algorithms that exist, these are just a few examples.