It's not just Avengers-slash-Magic, right
Unlimited cards are white-bordered instead, with brighter, bolder colors than the later (slightly different) Revised core set
That may sound narrow, but its amazing for grabbing utility creatures like Mother of Runes, Esper Sentinel, or anything else that gives you cheap power or combo potential
Alternatively, you can turn your ex-oriented Water deck into a bit of a one-point deck by consistently resurrecting and playing a Manaphy
C Common The Legendary Fisherman II X WATER Level 5 [ WarriorEffect ] ATK 2200 DEF 1800 This card's name becomes "The Legendary Fisherman" while on the field or in the GY
If you'd like further reading on some of the common arguments (and why they're incorrect), Patrick Chapin wrote a great article on this very subject that you can read here