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