Are all collectibles in Witcher 3 obtainable after the main quest?

Yes.

Yes, you can. There are various side quests and expansions that you can undertake even after completing the main story.

Yes.

Yes. There are side quests and other content.

Yes. Skellige related content is still available. You can go back to Skellige and do all the things you could before, like exploring the villages and fighting sea monsters.

[I don't think it'll necessarily satisfy your needs, but I'll try my best to recommend a novel that's most relevant to your description of your needs. The book,"Collection and Construction of a Foreign World", is a game novel written by the author, Gu Xingjian. The general plot of this novel is as follows: It could be considered as the first book that he had officially written. Because he wanted to write a long story on his first try, coupled with his poor writing style, he was already on the verge of death in the early stages. Later on, he actually signed a contract, which rekindled a little hope. However, for various reasons, he stopped writing more and more times, and the plot was almost forgotten. He still did not have the habit of making an outline. It was a little tiring to drag it out until here, so he ended it like this... ---------------------------- "The Strongest Contractor" was a military-war fantasy novel written by the author, Little Soldier. The general plot of the novel was: "Soldier Assault","I Am Special Forces","Black Hawk Down","Fast and Furious","Operation Red Sea","Wolf Warrior","Rush Out of the Amazon","Seal Team Six"…Enter the hot-blooded movie world. Complete the training and receive a large number of treasure chests and a mysterious gift. He had two super invincible armory with him. The gold ring on his left hand could open the Compass Mall, and the silver ring on his right hand had a CS armory. Barrett, AWM, and Fire God Gatling were all available. The skin could even add special effects! You can be a father with money! Unlimited firepower swept across the global battlefield! With an extremely violent manly hand, he launched the most passionate and barbaric charge towards the world's strongest private military contractor, PAC. ---------------------------- "The Subversion of Online Games Against Time Travel" was a novel written by God of Wood. The general plot of this novel was: The nine floating sky continents with 1080 sky cities were the world of the NPCs, while the players had to conquer the entire world beneath their feet…wielding the top-grade technological weapon for Berserkers, the Light Sword of the Millennium Light, and mastering the technological weapon for Archers, the Spiral Twist Force Booster…What if I, a Berserker, mastered a Golden Sniper Cannon when the Fallen Arrow was paired with the Spiral Twist Force Booster? A fantasy online game with unlimited data flow, and here it is…I want the Silver-Winged Spaceship that goes to the Sky Continent and the main city in the sky…What if all of this is true and I can bring it back to the Heavenly Star Sacred Zone? Then what would happen? ---------------------------- The Endless World Collectors was a sci-fi time-travel novel written by the author Yan Wuhui. The general plot of this novel was: Sun Wukong's Golden Cudgel, Jack Sparrow's Black Pearl, Iron Man's battle suit, Thor's Hammer, Amagasaki Ichigo's Moon Slaying, and even Shinji's first machine are all part of my collection. ---------------------------- "Offering Truth to a Beautiful World" was a light novel written by the author, Armed Research Ship. It was a fantasy novel. The general plot of this novel was: Su Wen came to the other world and obtained a system space. As long as he completed the mission, he would be able to obtain all kinds of 'truths'. There was a small truth known as the Glock 18, a medium-sized truth known as the Kalashnikov rifle, a large-scale truth known as the APF89 anti-tank rocket, a super truth known as the mushroom cloud, and even the ultimate truth from future technology…Su Wen decided to let the truth spread throughout this world of swords and magic. The original name was "I Have an Equipment Warehouse in the Other World", urging update group: 948520322. ---------------------------- Infinite Game Traverser was a sci-fi time-travel novel written by Moonlight Kill. The general plot of the novel was: Bye-bye to the rising job! Fang Xing was burned by the ball of lightning and became one of the shuttlers in the vast game battlefield. Why is my system different from others? Others can join the battlefield, but why can I only appear after the war? And why are my missions all about collecting waste? In short, the post-battle clean-up system has been bound. Good luck to the host! ---------------------------- "I'll Point the Way to the DNA" was a novel written by Feng Chengxian. The general plot of the novel was: "2019 DGN Allard Storyline Fictions", also known as "Herder's Memoirs","Dungeon and Ghostblade","Dungeon Krypton Gold Guide" This history began 500 years ago, when Tyranno-King Barkel crossed the Silent City and arrived in the Heavenly Realm. That year, the magical civilization of the Heaven Realm was brilliant, but it was killed by the Tyrannosaurus King. The Heaven Realm then entered the era of mechanical civilization. That year, the Delos Empire was very ambitious. They conducted transfer experiments one after another, and the nine apostles fell for it. That year, a young man named Fan Feng broke the chains on the ghost's hand! This was a brand new Dungeon of Fame. The map was huge. If you walked from Lorraine to Hendon Mare, you would have to cross half of Asia! This is Allard who was reborn from the ashes, a peace-loving celestial, a frank and honest Dark Elf, a goblin who never lies, a kind and kind-hearted Herder…and our adventurer who never takes back the money he found! The nostalgic equipment, Autumn Leaf Blade, Brahma Wind Coat, Black Bamboo Bracelet, Scale Rock Three-piece Set, Vengeful Spirit Set, Dragon Spine Set, Sky City… The nostalgic slogan, 5,000 to kill zombies, 30,000 to kill the entire map of the Sky Castle… This is a nostalgic trick. The entire GSD is worth one gold coin. Hurry up and buy it… The most orthodox history of the DNA novel, the most vast interstellar era, warriors, pick up your swords and march towards the light! ---------------------------- "The Movie and Television World's Collectors" was a sci-fi time-travel novel written by the infatuated Sea Cucumber. The general plot of the novel was: "Proud Swordsman", collect secret manuals-[Exorcism Sword Manual], combat power +666."Fast and Furious", collect luxury cars-Bugatti Veyron, combat power +233."Game of Thrones", collect beauty-"Dragon Mother" Daenerys, combat power-999! By the way, Shen Ze's main world was Marvel. Seven days later, Thanos would snap his fingers. ---------------------------- "Life in the Galaxy Online Game" was a virtual online game novel written by the author, Ice Star Rain. The general plot of this novel was: EVE？Interstellar citizen? Uninhabited Deep Space? Space engineer? No, no, no, it was the online life in the sandbox universe. Perhaps this was the beginning of the matrix revolution. But no matter what, he had to dig some ore and build a cruiser first. There were actually six new universe occupations here. They could become high officials above tens of thousands of people from the start, or they could become celebrities without worrying, or they could become rich people who spent money like dirt without any effort. In addition, there were hackers everywhere in the universe, engineers who created everything, and the God of War who commanded the fleet to wipe out everything. Other than a base and a cruiser for each person, there were also mechas and a starfield for each person to manage? What was that? Every room on the cruiser could be expanded into a building. The armor could become a wall, the main cannon could become a cannon, the engine could become a power plant, and it could even dig into the ground automatically to mine. The main base even threw me a set of equipment? Let's read it first and try it out... ---------------------------- "Guide to the Cultivation of an Interstellar Overlord" was a sci-fi novel written by Poinya. The general plot of the novel was: What was this? Space junk, pick up a piece, what is this? Space junk, pick up a piece, what is this? Space junk, pick up a piece… Hand over the space junk you picked up to the base manager and you will get a gun and a power armor… Wait, drones, warships, Gundam? Was this something that could be exchanged? On an inconspicuous abandoned planet in the vast universe, Wu Que spent a year and a half to finally activate a small base. When he summoned a creature called 'player' through the special central control system of the base, his space journey truly began.

Yes. In Witcher 3, once the main story is completed, the game doesn't stop you from collecting all the items. There are different types of collectibles scattered across the vast game world. Some are hidden in caves, some are rewards from side quests, and others can be found in monster lairs. Since the world is still accessible after the main story, you have the opportunity to explore every corner and collect every single item if you so desire.

No. While many heroes can be gained from the story in King's Raid, there are also some heroes that are obtained through other means, such as special events or gacha systems. For example, limited - time event heroes are often not part of the story - based acquisition.

In my opinion, starting with the main quests in Velen like 'The Bloody Baron' is a great start. It sets the tone and introduces important characters. Then move on to some of the related side quests in the area that expand on the story and characters you've met. After that, head to Skellige and follow the main quests there which often have a more epic and mythical feel.

In general, yes. Game developers often want players to have the freedom to fully explore the game world for hidden treasures even after the main story is completed. This gives players more incentive to keep playing and exploring. However, there may be some special cases where certain treasures are only available during the main quest or are lost forever if not obtained at a specific point in the main quest. But overall, you should have a good chance of finding all hidden treasures after finishing the main quest.