Here is the full list of all 50 Battlefield 1 achievements. It takes around 60-80 hours to unlock all of the achievements on Windows.
Perform a melee kill on 10 enemies anywhere in the campaign
Complete Nothing is Written
Collect one Field Manual in the campaign
Complete one challenge in the campaign
Win 1 round of Operations in multiplayer
Using a bolt action rifle, kill an enemy Scout in multiplayer
Complete 25 Squad Orders in multiplayer
Earn 450 Warbonds in multiplayer
Reach Rank 10 in multiplayer
Reach Assault Rank 2 in multiplayer
Reach Medic Rank 2 in multiplayer
Reach Scout Rank 2 in multiplayer
Reach Support Rank 2 in multiplayer
Reach Rank 1 with all 4 Infantry classes in multiplayer
Complete Friends in High Places
Complete Through Mud and Blood
Complete Avanti Savoia!
Complete The Runner
Unlock all Codex Entries in Friends in High Places
Unlock all Codex Entries in Nothing is Written
Unlock all Codex Entries in Through Mud and Blood
Unlock all Codex Entries in Avanti Savoia!
Unlock all Codex Entries in The Runner
Find the hidden Cavalry Sword and take down an enemy on the French countryside in the campaign
Kill 5 enemies by using dynamite in the campaign
Kill all 3 Ottoman officers in Young Men's Work with melee kills in the campaign
Complete the campaign on Normal difficulty
Complete the campaign on Hard difficulty
Collect all Field Manuals in the campaign
Complete 10 challenges in the campaign
Complete all challenges in the campaign
Spend 30 minutes in-game as French Republic Medic
Kill 4 enemies with the Trench Raider Elite Class
Kill 25 enemies with the St Chamond Heavy Tank
Perform one kill with each of the 5 primary Weapon Assignments weapons
Play all "In the Name of the Tsar" operations
Kill 25 enemies with the Lance as Cavalry
Win 5 games of Supply Drop
Play a round on all "In the Name of the Tsar" maps
Perform a kill with all "In the Name of the Tsar" weapon variants
Perform a roadkill in a Sea Vehicle
Complete 1 Service Assignment
Complete the Gallipoli Operation
Kill 15 enemies with the L-Class Destroyer
Perform a kill with all "Turning Tides" weapon variants
Perform a melee kill on a Flametrooper Elite
Perform 1 kill with the Livens Projector
Perform 1 kill with the Broken Bottle
Destroy 5 airplanes while in the Behemoth Airship L30
Perform a kill with all "Apocalypse" weapon variants