https://www.pcgamer.com/fallout-4-echo-mod-turns-the-wasteland-into-a-musical-about-employment/

The best Fallout 4 mods let you customise the wasteland. Be that through settlements and crafting, visual improvements and weather, or new locations and adventures there's pretty much something for everyone. With 510 lines of dialogue and four sing-a-longs, Kilosandwich's Echo transforms the Boston Commonwealth into musical about employment. I've no idea which category that best fits. 

I do however know we should expect one fully-voiced quest that last two hours and contains multiple endings, a plethora of puzzles, and "oodles of player choice". With music from Bing Crosby, Leonard Warren, Pat and Shirley Boone and a number of other 20th century crooners, Echo also invites players to "embark on a quest to discover the cause of a raft of disappearances, and find yourself swept up into an exciting and musical journey."