Here is the full list of all 53 FateEXTELLA achievements.
Obtained all achievements.
Defeated a total of 5,000 Aggressors.
Cleared all stages on VERY HARD difficulty.
Succeeded 100% completion rate in the gallery.
Recorded all Mystic Codes in the gallery.
Completely cleared Artoria Pendragon's sidestory.
Cleared all Servants' sidestories.
Completely cleared Archimedes' sidestory.
Completely cleared Elizabeth Bathory's sidestory.
Completely cleared Gilgamesh's sidestory.
Completely cleared Iskandar's sidestory.
Completely cleared Jeanne D'Arc's sidestory.
Completely cleared Karna's sidestory.
Completely cleared Lü Bu's sidestory.
Performed 200 Extella Maneuvers.
Raised 3 Servant's Kizuna level to 30.
Prevented a Sector Trap 30 times.
Upgraded one Install Skill by +20.
Completely cleared Medusa's sidestory.
Recorded all Install Skills in the gallery.
Raised a Servant's Kizuna level to 30.
Completely cleared Nameless' sidestory.
Completely cleared Gawain's sidestory.
Completely cleared Li Shuwen's sidestory.
Defeated a total of 1,000 Aggressors.
Completely cleared Cú Chulainn's sidestory.
Cleared the Golden Poem arc.
Cleared Artoria Pendragon's hidden side mission, then defeated her, on four different stages.
Allied with Tamamo no Mae in the Golden Poem arc.
Performed 50 Moon Crux/Drives.
Cleared the Dawn arc.
Defeated Nero Claudius in the Orchid Poem arc.
Revealed the true name of your Noble Phantasm 20 times.
Conquered a total of 100 sectors.
Prevented a Sector Trap for the first time.
Defeated Tamamo no Mae in the Dawn arc.
Succeeded 25% completion rate in the gallery.
Cleared the Orchid Poem arc.
Defeated Altera in the Orchid Poem arc.
Cleared the Flame Poem arc.
Defeated Altera in the Flame Poem arc.
Cleared Artoria Pendragon's hidden side mission, then defeated her, once.
Upgraded one Install Skill by +10.
Defeated Tamamo no Mae in the Flame Poem arc.
Equipped a new Mystic Code.
Obtained an EX rank in the results.
Performed a Moon Crux/Drive for the first time.
Equipped an Install Skill for the first ime.
Cleared the 1st stage of the Flame Poem Arc.
Switched with a vice general for the first time.
Revealed the true name of your Noble Phantasm for the first time.
Performed an Extella Maneuver for the first time.