In the battle between Absorb and other three-mana counters Absorb would almost always win out if it was easily castable, and it was even a small incentive to choose white over black as a secondary color
One thing to note is they regularly have sales on high rarity cards, so it's worth checking out their twitter before you head in to see if you can snag a deal
Funnily enough, Samurott could use a partner like that Blastoise, as its attack scales with attached energy, but its primary purpose will be its ability to swap out both actives for free every turn
From the hand, among other things: Monster Cards can be Normal Summoned/Set, Pendulum Monsters can be activated in the Pendulum Zone, Spell Cards can be activated, Spell/Trap Cards (except Field Spell Cards) can be Set in the Spell & Trap Zone, and Field Spell Cards can be Set in the Field Zone