Plugin Suggestion: https://www.spigotmc.org/resources/otd_mythictweak.77129/
MythicMobs is an amazing plugin to create and add all sorts of cool custom mobs/bosses. Oh the Dungeons You'll Go allows epic and huge dungeons to spawn on servers. I think OTD_MythicTweak would be great because it allows server owners to have the custom mobs spawn in the OTD dungeons. This could make the dungeons even more fun.