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 "Return" ending
Acquired all skills
Upgraded all Prosthetic Tools to their limit
Defeated all bosses
Attained the "Shura" ending
Defeated "Isshin Ashina"
Attained the "Immortal Severance" ending
Attained the "Purification" ending
Defeated "Sword Saint Isshin Ashina"
Defeated "Great Shinobi - Owl" at the Hirata Estate
Upgraded Vitality and Posture to their limit
Grasped the inner mysteries of any combat style
Used Lapis Lazuli to upgrade any tool to its limit
Defeated the "Demon of Hatred"
Defeated the "Great Colored Carp".
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 Ninjutsu Techniques
Used the Mortal Blade to sever the Guardian Ape's undying
Defeated the "Great Serpent".
Acquired all Prosthetic Tools
Defeated the "Guardian Ape"
Caught the Folding Screen Monkeys
Defeated "Genichiro Ashina"
Defeated "Lady Butterfly"
Defeated "Gyoubu Masataka Oniwa"
Returned from the dead using "Resurrection" for the first time
Encountered the Memorial Mob
Acquired the Shinobi Prosthetic
Received the "Kusabimaru" from Kuro