Recommended Mace Enchantments
Density V
More smash damage per block fallen - the mace's core damage enchantment. (Density, Breach, Smite and Bane are mutually exclusive.)
Breach IV
Alternative to Density: reduces the target's armor effectiveness on hit - great vs armored mobs.
Wind Burst III
Launches you upward after a smash attack - chains smashes and softens landing.
Unbreaking III
Durability lasts about 3x longer.
Mending I
XP repairs the mace - important since maces need a heavy core and are costly to replace.
Fire Aspect II
Optional: extra fire damage on hit - a familiar sword-style extra.
FAQ
What are the best mace enchantments?
Density V (or Breach IV), Wind Burst III, Unbreaking III and Mending. Density, Breach, Smite and Bane of Arthropods are mutually exclusive.
Density or Breach on a mace?
Density V for raw smash damage (scales with fall distance); Breach IV to ignore up to 60% of the target's armor. Pick based on whether you fight unarmored or armored mobs.
What does Wind Burst do?
After a smash attack, Wind Burst launches you back into the air, letting you chain consecutive smashes and negate most fall damage.
How do I get a mace in Minecraft?
Craft it with a heavy core (from ominous vaults in trial chambers) plus a breeze rod - then enchant it carefully, because the heavy core is rare.