When you defeat an enemy, you'll get a reward card that will be added to your deck
They are, however, weak to Fighting type Pokemon though, in my experience of both casual and tournament play, Fighting types are fielded more rarely than other Pokemon (admittedly, that doesnt seem to be the case in general, however!)
Jellicent looks like a bigger, badder version of Budew plus it can block Tools too
The chapter ability matching the new number will trigger
Ill put some of the highlights in order, then gold, just for people to know what they can expect out of these: Kenrith, the Returned King Akroma's Will Urza, Lord High Artificer Counterspell Cryptic Command Rhystic Study Yawgmoth, Thran Physician Bolas's Citadel K'rrik, Son of Yawgmoth Ragavan, Nimble Pilferer Ancient Copper Dragon Primeval Titan Atraxa, Grand Unifier Tymna the Weaver Isshin, Two Heavens as One Thrasios, Triton Hero #45
Card Number / Rarity: SWSH138 / Promo Card Type / HP / Stage: Darkness / 110 / Basic Card Text: (This card cannot be used at official tournaments.) Attack 1: [2] Bite (30) Attack 2: [1DD] Berserker Blade (100) This attack also does 20 damage to 2 of your opponent's Benched Pokemon