How do I make an advanced pathfinding NPC that can pathfind from anywhere?

I am currently working on a game which randomly generates a large map. I need to make an enemy that can pathfind to the player from any point in the map. I don't know how to approach this without getting a lot of problems with the path being blocked. Some sort of way to have an ignore list for pathfinding or just a way to pathfind even with blocked paths would be helpful. I'm not really that experienced with pathfinding so any advice would be nice.