The base Civilization VI features exactly one hundred Steam achievements that can be obtained through gameplay. DLCs have, as of the Khmer and Indonesia Civilization & Scenario Pack, added 53 additional achievements, the Rise and Fall expansion pack adds an additional 38 achievements, and Gathering Storm adds a whopping 50 new achievements, bringing the total number to 241.

https://www.reddit.com/r/civ/comments/5fgkc9/civilization_vi_100_achievements_tips/

• 100th Anniversary: As America make a National Park of Crater Lake and both tiles of Yosemite in one game.
• 12 Labors of Hercules: Win a regular game at Immortal difficulty or harder.
• 12 Olympians: Have 12 Policy Slots as Greece.
• 2016 Ready: Playing as Brazil, complete both Estadio Do Maracana and Christo Redentor in one city.
• A Case for War: Declare a formal war.
• A Revolution Without Dancing: Change your government.
• After Antiquity: Win a regular game with a Classical Era start.
• Alfred Wegener's Legacy: Win a regular game on the Pangaea Map.
• Arabian Knights: Conquer a city with a Mamluk.
• Archimedes Bath: Get 5 Tech boosts in 1 turn.
• Army of Cthulhu: Levy the military of Nan Madol.
• Be the Change You Wish to See In the World: Win a regular game as Gandhi.
• Bronze Horseman: Win a regular game as Peter the Great.
• Buying Your Blue Jeans and Listening to Your Pop Music: Win a regular game with a Culture victory on any difficulty with any leader.
• Captain of Industry: Win a regular game with an Industrial Era start.
• City of Kongo: Playing as Kongo, have a capital city with a population of 30.
• Civ 6 Civets System: Get 5 Civic boosts in 1 turn
• Crouching Tiger Hidden Cannon: Playing as China, end a turn with 5 Crouching Tigers on Great Wall tiles
• Crusader King: Win a regular game as Frederick Barbarossa
• Daughter of Isis: Win a regular game as Cleopatra
• Dirty Dozen: Win a regular game on a Huge Map
• District 12: Build every district type in one city and the Colosseum.
• Eight is Enough: Win a regular game on a Standard Map
• Elixir of Immortality: Win a regular game as Qin Shi Huang
• Emperor's New Groove: Win a regular game at Emperor difficulty or harder
• Emperor of Brazil: Win a regular game as Pedro II
• Epic of Gilgamesh: As Sumeria, have the first Great Work of Writing
• Escort Service: Put two units into a formation
• Everything is Awesome!!!: At the start of the turn have an Ecstatic city.
• First to Civilize: Win a regular game as Gilgamesh
• Flight Slingulator: Airlift a level 3 Slinger
• Irish Heartbeat: Win a regular game at Chieftain difficulty or harder
• Machiavelli's Great Work: Win a regular game at Prince difficulty or harder
• Naming Rights: Name a unit
• New Orleans Style Spanish Rice: Become Suzerain of a City-State
• Nirvana: Win a regular game with a Religious victory on any difficulty with any leader
• Riffle and Bridge: Win a regular game on the Shuffle Map
• Six Shooter: Win a regular game on a Small Map
• Splitting the Atom: Win a regular game with an Atomic Era start
• Tectonic Shift: Win a regular game on the Continents Map
• The Divine Right of Kings: Win a regular game at King difficulty or harder
• The Test of Time: Win a regular game with an Ancient Era start
• Through the Digital Age: Win a regular game with an Information Era start
• Warlording Over Others: Win a regular game at Warlord difficulty or harder
• Voyage of the Mayflower: Found or conquer a city on a different continent
• Die Another Day: Neutralize a Governor with a Spy
• Subject Matter Expert: Have a Governor with every promotion
• What Could Possibly Go Wrong?: Have an improved Amber resource in a city with a Zoo and an Archaeological Museum at the start of the turn
• Peacekeeper: As Wilfrid Laurier, successfully complete an Emergency
• Real Estate Disclosures Required: Have a district be pillaged by 3 different random events
• Surprise Attack: Move a military unit into an enemy's owned tile using a Mountain Tunnel (or Qhapaq Nan)
• The Art of Telling Plain Truths: Win a Diplomatic Victory
• The Sunny Way: Win a game as Wilfrid Laurier
• I'm going to break the wheel: Earn three Golden Ages in a row
• For Queen and Country: Playing as England on a Huge map, have a city on every continent at the start of the turn
• For Sparta!!!: Win a regular game as Gorgo
• Four Corners Offense: Win a regular game on a Tiny Map
• Game, Settler, Match: Win a regular game at Settler difficulty or harder
• Gift From the Storm God: Receive a Strategic Resource from Hattusa
• Give Peace a Chance: Playing as India on a Huge map, receive +35 Faith in one turn from the Satyagraha ability
• God-Like: Win a regular game at Deity difficulty
• Here's Looking At You Kid: Win a regular game on a Duel Map
• Huey Tlatoani: As Aztecs on a standard-sized map, attack an opponent while receiving a +16 Combat Strength bonus for having all of the luxuries
• I Am Amused: Win a regular game as Victoria
• If You Build It, They Will Come: Have 6 Improvements at one time.
• Investment Banking: Put a city under siege
• Island Hopping: Win a regular game with a Domination victory on any difficulty with any leader on a Huge Island Plates map.
• Katsu!: Win a regular game as Hojo Tokimune
• Bromance: Achieve the maximum Alliance level with Gilgamesh
• Land Party: Play a multiplayer game
• Legends of the Hidden Temple: Build a Colossal Head adjacent to a Holy Site with a Temple.
• Let Teddy Win: Win a regular game as Theodore Roosevelt
• Mission to Mars: Win a regular game with a Science victory on any difficulty with any leader
• Ibutho: As Shaka, train a Corps of Impi using the Ikanda district
• Drama Queen: Join or be the target of 3 Emergencies in a single game
• Loire Valley: Create 5 Châteaux in one city with the Wine resource.
• Luftballons: Use a bomber class unit to detonate a nuclear device, as long as its base and 9 Observation Balloons are located on the continent of Nena at the time of detonation.
• Man on the Moon: Win a regular game with a Science victory on any difficulty with any leader with a captured Egyptian city -- having also activated Newton and Darwin
• Mare Nostrum: Win a regular game on the Inland Sea Map
• Meiji Restoration: Playing as Japan, have a district with 6 adjacent unpillaged districts
• Missed That Day in History Class: Clear nuclear contamination with a Roman Legion
• Modern Major General: Win a regular game with a Modern Era start
• Montezuma's Revenge: Win a regular game as Montezuma
• Mwene Kongo: Win a regular game as Mvemba a Nzinga
• Nobody Expects the Spanish Inquisition: Launch an Inquisition as Spain
• Non Sufficit Orbis: Win a regular game as Phillip II
• Oneth By Land Twoeth By Sea: Have an Army of land Units and 2 Armadas
• Oratorical Skills: Win a regular game as Pericles
• Out of the Dark Ages: Win a regular game with a Medieval Era start
• Pizza Party!: Activate Leonardo da Vinci in New York with Great Works from Michelangelo and Donatello -- and a sewer -- all in that city
• Renaissance Man: Win a regular game with a Renaissance Era start
• Repo Man: Steal a Great Work of Art and don't get caught
• Rome If You Want To: Win a regular game as Trajan
• Scythian Horse Rush: Playing as Scythia have 10 Saka Horse Archers in your army
• Secret Service: Have top secret access with five civilizations in one game at once.
• Selfie: Win a regular game with a Culture victory with your leader in the game as your opponent as well
• Seven Wonders of the Post-Apocalyptic World: Launch a weapon of mass destruction with a unit and have it pillage seven wonders
• Silver Anniversary: Possess 6 Silver luxury resources at the start of the turn
• Sultan of Egypt: Win a regular game as Saladin
• Ten Commandments: Win a regular game on a Large Map
• The Divine Right of Kings: Win a regular game at King difficulty or harder
• The Origin of Species: Activate Darwin adjacent to the Galapagos Islands
• The Taste of Victory: Win a regular game on the Island Plates Map
• Third Crusade: Playing as Frederick Barbarossa, conquer the city-state of Jerusalem
• Trans-Siberian Railroad: Playing as Russia, have a city that is at least 60 tiles away from your capital, connected by a Trade Route and road at the start of the turn.
• Unique Snowflake: Win a regular game on Fractal Map
• Walk Like an Egyptian: As Egypt build a Sphinx adjacent to the Pyramids both on Floodplains
• Valois Dynasty: Win a regular game as Catherine De Medici
• Varangian Guard: Win a regular game as Harald Hardrada
• Warrior Queen: Win a regular game as Tomyris
• We Are The Champions: Win a regular game with a Religious victory with your dominant religion being Zoroastrianism and at the time of victory you are the Suzerain of Zanzibar
• Veni, vidi, vici: Win a regular game with a Domination victory on any difficulty with any leader
• Viking Raid: Capture a settler with a Longship
• Elcano's Revenge: Be the first player to circumnavigate the world after Ferdinand Magellan has been recruited by another player
• Airing Your Grievances: Win a Diplomatic Victory Resolution and use it to reduce another player's progress toward that victory
• A Smashing Victory: Win a regular game as John Curtin
• uSuthu! uSuthu!: Win a regular game as Shaka
• Attack of the Drop Bear: Lose a unit to the perils of Australia in the Outback Tycoon scenario
• Envoy Convoy: After building the Apadana wonder, construct 7 additional wonders in the same city
• I Quenched Your Thirst For Blood: Playing as Scythia, recapture one of your founded cities from Persia
• King of the Four Corners of the World: Win a regular game as Cyrus
• Some Wine For Your Soldiers?: Playing as Persia, conquer the original Scythian capital within 10 turns of declaring a surprise war on Scythia
• Greatest Is As Greatest Does Playing as Macedon, conquer a city containing both the Great Library and Great Lighthouse wonders
• He Named Them All After Himself?: Settle four cities in Conquests of Alexander on any difficulty
• Never Lost a Battle: Win a regular game as Alexander
• No More Worlds To Conquer: Win Conquests of Alexander on any difficulty
• Resplendent Panoply: Possess all of the following after conquering a city in Conquests of Alexander: Hoplite, Saka Horse Archer, Maryannu Chariot Archer, Immortal, and Varu
• You're the Demonstrably Greatest: Achieve the highest possible rank in Conquests of Alexander at Deity difficulty
• Nobody's Business But the Turks: As the Ottomans, capture another Civilization's capital and then rename it
• Padishah Efendim: Win a game as Suleiman The Magnificent
• Victory Belongs to the Most Persevering: Achieve a Heroic Age
• Desperate Times Call For Desperate Measures: Assign a Dark Policy to your Government
• gg nub: Win a regular game as Amanitore
• More Wind for the Wind God: Win Gifts of the Nile on any difficulty
• Overclocked Conviction: After building the Jebel Barkal wonder, earn 28 Faith per turn on its tile
• Pyramid Scheme: As Nubia, earn six different adjacency bonuses on a Nubian Pyramid
• Sea of the Bow: Playing Gifts of the Nile as Nubia, found a coastal city on the Mediterranean Sea
• That's Some Good Kerma: Playing Gifts of the Nile as Nubia, win on Deity difficulty
• The 25th Dynasty: Playing as Nubia, liberate the original Egyptian capital in a liberation war with the capital's conqueror
• Total A-Nile-hilation: Playing Gifts of the Nile as Egypt, win on Deity difficulty
• Claim the Fourth Cataract: Playing as Egypt in a regular game, conquer the original Nubian capital within 10 turns of declaring a formal war on Nubia
• From Med to Red to the Land of the Dead: Playing Gifts of the Nile as Egypt, conquer Irem and Punt
• From Peonies to Doricheon: Win a regular game as Queen Seondeok
• A small Country, a great people, so sorely tried: Win a regular game as Queen Wilhelmina
• Tu Meke: Win a game as Kupe
• Nobel-er than the Noblest: Achieve first place in all three Nobel Prizes in the same game
• Thalassocratophile: Have 5 cities on landmasses 5 or less tiles with Indonesia
• Many Signs and Wonders: Build all 3 Wonders in the Path to Nirvana scenario
• Raid Healer: With a Guru Heal 7 religious units with one action
• Try To Snatch the Pebble From My Hand: Have a Warrior Monk with 4 Promotions
• All Beneath the Wings of Garuda: Win a regular game as Gitarja
• Wat is Love: Build Angkor Wat and a Wat in Angkor Wat
• What is Matter? Nevermind.: Win the Path to Nirvana scenario on Deity
• What is Mind? No Matter.: Win the Path to Nirvana scenario on any difficulty
• Cardamom and Mangos and Elephants: Win a regular game as Jayavarman VII
• Do You Have A Moment To Talk About Salvation?: Convert 3 opposing Holy Cities in the Path to Nirvana scenario
• Future is Now: Be the first to complete all the technologies in the Future Era in a game with 8 or more players