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