The best premodern era (4th to scourge) cards printed at common or uncommon at some point. The goal is powerful, but not broken. A nice place where old cards that used to be good enough, but have lost their place in modern era cubes or eternal formats. You have to work for your mana fixing, especially in enemy color pairs. Have fun building around a broken enchantment, various graveyard stuffs, cycling, beatdowns or goblins. The archetypes are squishy and the games are interactive.

Some personal choices
The only creature types that matter are goblins and dragons, to avoid great creature type update problems.
No morph
No shadow
No graveyard order matters cards