Modern Skyblock 3
Modern Skyblock 3 is the sequel to Modern Skyblock 2 (obviously :P). Modern Skyblock 2 was unique for that that it used Sky Resources for obtaining resources instead of Ex Nihilo, but since its release, a few other packs have used, making Modern Skyblock 3 not unique for that. Modern Skyblock 3 is unique for another reason: Unlike almost every other pack that has a progression line, it doesn't have any recipe changes (besides for those fixing exploits and allowing a few mods to work). Instead, it's entire progression line is based around quests, hence it features 1k+ of them. It also features 3 modes:
Kitchensink mode - You may play through any mod you want at any time, allowing you to become OP in the first few hours. There will still be many quests to complete that will keep you playing for a while.
Staged Mode - To progress through one mod you need to progress through another. Even though there are no recipe changes, not being able to use certain items adds a layer of difficulty. However, if you dislike a certain mod, you can usually simply rush through its quests.
Gated Mode - just like Staged Mode, but to unlock the next stage you need to hand in certain items from the required stages. That means that you need to progress through every mod and you can't simply rush through them.