Here is the full list of all 51 Red Dead Redemption 2 achievements. It takes around 200 hours to unlock all of the achievements on Windows.
Red Dead Online: Achieve MVP 3 times (in a round with at least 4 players).
Red Dead Online: Reach Rank 50.
Red Dead Online: Concurrently own 5 horses.
Red Dead Online: Craft 25 pieces of ammunition.
Red Dead Online: Purchase 5 camp improvements.
Red Dead Online: Play 5 Free Roam Events.
Deliver 5 camp companion item requests.
Study every animal across all states in Story Mode.
Skin every species of animal in Story Mode.
Earn 70 Gold Medals in Story missions.
Attain 100% completion.
Red Dead Online: Take part in a Series.
Red Dead Online: Achieve 5 gold belt buckles from awards.
Red Dead Online: Craft 20 items (excluding ammo).
Red Dead Online: Accept 10 Free Roam missions from characters around the world.
Red Dead Online: Reach Rank 10.
Find a permanent home for the squirrel statue.
Red Dead Online: Complete a Free Roam mission as part of a Posse with at least 2 members.
Red Dead Online: Successfully counter a rival Posse's Free Roam mission.
Complete all optional Honor story missions.
Red Dead Online: Form a Persistent Posse.
Red Dead Online: Sell 20 items to the Butcher.
Red Dead Online: Pick 25 Herbs.
Red Dead Online: Complete the Intro.
Find the graves of each of your fallen companions.
Catch a fish weighing at least 16 lbs (7.3 kg).
Complete one of the Collectable strands.
Survive 18 bear attacks and kill the bear each time in Story Mode.
Craft 30 unique items in Story Mode.
Complete 10 Stranger mission strands.
Play all mini games.
Survive 3 days holding a bounty of $250 in all states.
Discover the fate of Marko Dragic.
Complete a Companion Activity in each camp.
Complete 'Goodbye, Dear Friend'.
Complete 'A New Jerusalem'.
Spend $5000 across all shops.
Complete the Epilogue.
Complete 'Red Dead Redemption'.
Reach maximum or minimum Honor level.
Complete Chapter 5.
Complete Chapter 4.
Recover the stash from 4 homesteads.
Complete Chapter 3.
Upgrade each available component for a single sidearm or longarm weapon.
Reach max bonding level with a horse.
Complete Chapter 2.
Rob or loot $250.
Donate $250 to the gang tithing box.
Complete Chapter 1.
Complete 'Enter, Pursued by a Memory'.