This save has everything on the 100% completion list done except for Strangers, chance encounters, bushwhacked, gang hideouts, gangs, weapons, horse bonding, legendary animals, table games and robberies. 
This is like this because the objective either hasn't been unlocked or you'll certainly check it off while playing through the main story. 

I left 3 stranger missions to complete because you'll complete them by completing the legendary fish quest, exotics quest and the hunting requests, (which aren't unlocked through the story yet) but if you're going for 100% they play a major part in the collectables strain but they're also stranger missions. 

You'll have all weapons purchasable in stores but with no customisation, I did this so you can customise Arthur to your liking, he also has the default honour value so you can still choose whether to be good or bad.

You have the Legend Of The East Satchel through save modding but you cant see it, wait until you unlock the crafting mechanic from Pearson and you should then visually have the satchel.

You'll have the Missouri Fox Trotter, in my opinion the best horse in the game, but feel free to change once you unlock the horse stables.

This is just for people who want 100% not to do absolutely everything (study every animal, get gold badge for every mission, etc) <- Those aren't required for 100%.

Installation:
1. Once mod is downloaded you'll have to extract the file with a program like WinRAR
2. Go to File Explorer/This PC/Documents/Rockstar Games/Red Dead Redemption 2/Profiles/The 1 folder with random numbers and letters (its different for everyone), then drag and drop "SRDR30001" into the folder.