I’m curious what the community deems the necessary accessories for its Conan 2d20 libraries. These should preclude the Core Book and The Player’s Guide
As a backer, I have everything in digital, but here are the books I determined I needed on my physical shelf:
Conan the Thief
Conan the Barbarian unnecessary indulgence only because I’m so into Vikings
Conan the Pirate
Conan the Mercenary
Forthcoming in print:
Conan the King
Kull of Atlantis
Everything. 
I think Mercenary and Pirate are essential, for all the expanded options for combat presented. So many Conan exploits take place at sea or on large battlefields, most campaigns will inevitably suffer without the expanded rules to cover naval combat or massive battles. This also goes for detailed statistics for watercraft, and rules for pillaging and looting. The Book of Skelos is indispensable if you want to have any PC playing a sorcerer. Obviously I don’t know what will be in Conan the King, but I have a strong feeling it will a book I can’t do without either. Some GMs might need Horrors of the Hyborean Age, but I have no trouble designing my own monsters and haven’t picked it up. Pirate and Mercenary are my top picks.
I totally agree with you for precisely your reasons (with a slight reservation on Skelos; I find I don’t need any more magic than what is in Core, though I acknowledge you’re probably correct, were I ever to have a player running a sorcerer).
And I can assure you that, according to these criteria, King will be another of your must-haves. It details rising to the throne, political intrigue, nation-building and taxation, and (whereas Mercenary walks the GM and players through large battles) nations at war. It’s a very fine book, and I hope to run a long campaign with (naturally) King featured as the endgame.
This is a great topic, thanks for bringing it up! This is my favorite game on the shelf right now - really interested to hear about what everyone is getting from the various supplements.
My essential supplements are:
Conan the Thief, for the great heist rules and player options
Conan the Mercenary, for the battle rules and player options
Honorable mentions to:
Book of Skelos, for the rules on creating horrors and for sorcerous PC’s
Horrors of the Hyborian Age, for the extra monsters but certainly not necessary
Upcoming, really looking forward to seeing:
Conan the King, hoping to add options for longer campaigns
Conan the Adventurer, the setting and options sound exciting
Oh yes, I am waiting for King with baited breath! I cannot wait to add these options to my campaign.
You encouraged me to look again at Skelos. Though I don’t foresee myself using it soon, I totally need it now!
I just now ordered it.
I like a lot of the books and besides the Core book I usually bring the Barbarian, Skelos, & Merc with me to my games. I like all of the ones that I have and I am working on getting more. I still tend to like reading the physical copies more than PDFs even with a tablet. Waiting for the excitedly for Conan the Wanderer to come in print but the Kull of Atlantis is very nice as I have been putting the history of the Thurian age into my sessions. Honestly for myself if there is a good Gazetteer section about the world then i really enjoy reading the books.
Book of Skelos (one player is a charlatan)
Don’t forget the Charlatan and Mummery talents out of this book. They make for neat semi sorcerous players or foes. Modiphius also added a little to Alchemy with Petty Enchantments here as well and the Herbalism Talent. Big write up on the Astrology Talent and others mentioned.
Horrors of Hyboria
More critters are good. Though this game allows for reskinning opponents easily.
Conan the Mercenary (weapons and army rules)
Army rules can use tweaking but its nice to have for player involvement in big battles. Just remember to zoom in to the players one vs one fights or use squadron leader tactics.
Conan the Barbarian (one player is a bard and one a Berserker)
Love the expanded views in this book on the northern regions of the world. I tend to like the information about the different countries and city states out of all the books though.
Conan the Scout (great book)
Love the increased worldview into the Pictish wilderness and what some of the various tribes are like. This could be a campaign in itself.
Conan the Brigand (great book)
Conan the Thief (great book)
None of my players are big on being thieves yet but the information in here is good.
Conan the Pirate (ship combat)
For when i wish to delve into ship to ship combat in this age.
Nameless Cults (great information and archetypes)
This book has an expanded worldview on the deities of a country/region that I try to implement in some way into the hyborian world.
This is a really fantastic analysis. I’m glad you brought up those other features in Skelos. I don’t actually have my own copy yet myself but sure seems worthy of some love.
I agree with Valyar about everything being necessary in its physical form. Although having the pdfs is nice, and it’s not difficult to navigate them, I feel the need to have the physical copy of the book with me if anything relating to it can come out when playing.
Also I must confess to like this as much as to try and have everything as it’s just that great. So I’d really rather have it all just to both consider any possibility and give players the chance to take looks at it, just for future ideas at least. BTW, having the full range at hand can be the key to advance a campaign, just by getting hold of players’ ideas on the different books.
For example, a land locked mercenary campaign could become a pirate venture because one/some player/s liked what they saw at the book; disagreement on payment, looting, thievery or straight treason could be motivations to get away from their employer, and the sea the best way to do so.
So far I’ve got:
Corebook
Player’s Guide
Screen
Horrors of the Hyborian Age
The Monolith Sourcebook
Conan the Mercenary
Conan the Thief
Conan the Barbarian
Conan the Pirate
Conan the Brigand
Book of Skelos
Jewelled Thrones of the Earth
Ancient Ruins and Cursed Cities
Nameless Cults
and the Dice of course
I bought as a bulk pruchase: Core, Player’s Guide, Screen, 1xdiceset, Horrors, C the Barbarian, C the Pirate only coz I’m a huge Conan fan and rp’ing for 30+ years and had a back payment. I bought Horrors basically to have extra nasties even though the Core has a decent selection.
Next up is the Merc… on it’s way already.
Followed by the Brigand, the Thief, Jeweled Thrones, Ancient Ruins and Cults… SORTED!