All except the Secret Packs are pretty self-explanatory: They contain boosters with the cards indicated in their description
Quuador: A lot of this (almost all) was done by @justinator before I started collecting and before I joined this forum, but we both still discover new Pikachu cards almost monthly, even from as far back as 1999
There's also Hammer Crush Deal, which essentially makes Hammer Crush (a Mystical Space Typhoon with a discard cost) effectively free by setting Hammer Crush then immediately drawing a card, and decks playing it often forgo strategy in favor of simply cramming in Level 4 Normal Monsters with 1500 ATK (the strongest non-Tribute monsters in the format) along with a variety of generic boss monsters
Baylen, the Haymaker If reading through this list so far hasnt convinced you of MTGs Bloomburrow sets love of tokens, perhaps Baylen, the Haymaker will
Renegade Rallier Renegade Rallier basically requires you to replay fetch lands, but who doesnt love extra fetches
I dont believe it has anything to do with them being printed first and, in fact, I believe they were printed along side the main set