The Psycho Krieg and the Fantastic Fustercluck Add-on for Borderlands 3 has 7 achievements worth 190 gamerscore.
Defeat Psychoreaver.
Defeat Dr. Benedict.
Defeat Locomöbius.
Defeat Evil Lilith.
Complete mission "Enter the Psychoscape".
Explore all of Vaulthalla.
Complete all side missions and crew challenges in Krieg's Mind.