Fallout 4: Far Harbor

For me, Far Harbor is the best add-on for Fallout 4, it not only gives a new wonderful location to explore, armor, weapons, etc., but also gives a wonderful and interesting plot with equally wonderful characters, the add-on literally complements the plot of the game, reveals the world of the game, revealing details of the institute, Nick Valentine and other characters. Literally bombards everyone with new and interesting information and characters. Also, the addition is not linear, which allows you to get a different ending to the adventure.