Here is the full list of all 34 Sekiro: Shadows Die Twice - there are GOTY Edition achievements worth 1,000 gamerscore.
All achievements have been unlocked.
Attained the "Shura" ending
Defeated all bosses
Defeated "Isshin Ashina"
Acquired all skills
Upgraded all Prosthetic Tools to their limit
Attained the "Return" ending
Attained the "Purification" ending
Upgraded Vitality and Posture to their limit
Defeated "Great Shinobi - Owl" at the Hirata Estate
Defeated the "Demon of Hatred"
Used Lapis Lazuli to upgrade any tool to its limit
Acquired all Ninjutsu Techniques
Used the Mortal Blade to sever the Guardian Ape's undying
Defeated the "Great Colored Carp".
Grasped the inner mysteries of any combat style
Attained the "Immortal Severance" ending
Defeated "Sword Saint Isshin Ashina"
Defeated the "Divine Dragon" and obtained the "Divine Dragon's Tears"
Fully upgraded the "Healing Gourd"
Defeated the "Corrupted Monk"
Traveled to all areas of the game
Defeated "Great Shinobi - Owl"
Acquired all Prosthetic Tools
Defeated the "Guardian Ape"
Defeated the "Great Serpent".
Caught the Folding Screen Monkeys
Defeated "Genichiro Ashina"
Encountered the Memorial Mob
Defeated "Gyoubu Masataka Oniwa"
Defeated "Lady Butterfly"
Returned from the dead using "Resurrection" for the first time
Acquired the Shinobi Prosthetic
Received the "Kusabimaru" from Kuro