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