Full list of all 66 Fallout 76 (Windows) achievements worth 1,400 gamerscore. It takes around 80-100 hours to unlock all of the achievements in the base game.
The base game contains 60 achievements worth 1,255 Gamerscore, and there are 2 DLC packs containing 6 achievements worth 145 Gamerscore.
Leave Vault 76
Complete "First Contact"
Complete "Final Departure"
Complete "Second Helpings"
Complete "Into the Fire"
Complete "Recruitment Blues"
Complete "Heart of the Enemy"
Complete "Key to the Past"
Complete "Coming to Fruition"
Complete "Bunker Buster"
Complete "One of Us"
Complete "Officer on Deck"
Build a C.A.M.P.
Build 20 C.A.M.P. Items
Build 100 C.A.M.P. Items
Complete "Mistress of Mystery"
Complete "Personal Matters"
Complete "Queen of the Hunt"
Complete the "Monster Mash" Event
Win the "Scorched Earth" Event
Win the "Breach and Clear" Event
Join 20 Teams
Craft 5 Pieces of Armor
Craft a Weapon
Reach Level 100
Read 20 Magazines
Be at Ground Zero of a Nuclear Blast
Fully Rank Up one Perk
Pick 50 Locks
Hack 50 Terminals
Mod 50 Weapons
Complete 5 Challenges
Complete 20 Challenges
Revive 20 Fallen Players
Possess 10,000 Caps
Play a Holotape Game
Kill 5 Giant Creatures
Discover 100 Locations
Kill a Wanted Player
Kill Another Player
Kill 20 Players
Kill 300 Creatures
Gather 200 Pieces of Junk
Take 20 Photos
Collect a Bobblehead
Collect 10 Bobbleheads
Reach Level 10
Reach Level 25
Reach Level 50
Complete "I Am Become Death"
Complete "The Elusive Crane"
Find the Overseer
Complete "Buried Treasure"
Complete "All That Glitters"
Complete Sofia's story
Complete Beckett's story
Become allies with Foundation
Become allies with Crater
Gain 300 gold bullion
Gain 1500 gold bullion
Complete “The Catalyst”
Earn Elder Rewards from a Daily Op
Craft a 1 star legendary mod, a 2 star legendary mod, and a 3 star legendary mod
Lead and complete "Union Dues" and "From Ashes to Fire"
Complete 10 Favors for people in The Whitespring Refuge
Kill 100 Trogs with an Auto Axe