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