In the very first scenario, if you are earning the loot cards, you gain what I consider the most important card of the set. It is also the best card of AD5, Revelation Quill.
Ranged - Venomous Heavy Crossbow +2, or Venomous Dart +2, or Acidic Sling +3. By this time, you will want all of them.
Melee - Flaming Ranseur +3, Dancing Scimitar +2, Keen Rapier, Keen Scythe +2. Just keep collecting them all.
Divine - Sunburst. It's the spell you've been waiting for.
Arcane - Two most excellent spells. Disintegrate and Gozreh's Trident.
Light - Bearskin is better than the alternative
Heavy - Fortified Breastplate. It's surprising how useful it's reveals are.
Shield - Spell Ward Shield. This is the reason you take one armor card feat and no power feat. Get it and keep it. The best armor in AD5
Mossy Disk. For toons that have trouble closing, this item is a real blessing (Amiri)
Pyromaniac Mage. Many good allies, but this one adds fire to both arcane and divine attacks
Blessing of Thassilonian Virturues. It's a good one, but can use it's special function only by the toon that carries it.
I'm sorry that I didn't narrow down some of the choices, But by AD5 were are seeing some of the best the game has to offer. But wait....AD6 gets better!