Used this resource on my server, pretty good! Would be glad if you can add bosses like Orc lord , Wraith King and Brood Mother (for each type)
:)

[Mob Pack] Buguser's Dungeon Mob Pack ⚔ 1.13 and 1.12 supported! V. 1.3
24 dangerous monsters for your dungeons! Optional random mob spawners included.