Level 1

Level 1 monsters are monsters who have one red star near the top of their card. This is the lowest level allowed for any monster in the game, for obvious reasons.

Level 1 monsters require no Tributes in order to be Normal Summoned. Their stats may vary, but generally fall in between the 0-1000 range. In fact, many of these monsters do have 0 ATK and DEF.

The following cards affect all Level 1 monsters:
 * Discus Dragon (provided the monster can be Special Summoned in that way)
 * Oriental Head
 * Blood Tear the Final Trinity
 * Carrion Pidgeon
 * Mother Earth Polluted
 * Ocean Dweller - Savage
 * Rainbow Tail

To see a list of Level 1 monsters in HCCG, see this page.