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