Everyone's got their own custom list. Here are some of mine (several of which are shamelessly "modified" from other people's suggestions). This is a cut-n-paste from another document, so please excuse the length.
BLOODED The item is created for use by one and only one race. To do this, the item is forged with the blood of the enemies of this race. When someone without the blood of the chosen race (but not a racial enemy) uses this item they gain two negative levels for as long as they wield the item. Racial enemies who possess this item they gain four negative levels and lose one hit point per turn as long as it remains in their possession. These weapons will usually be referred to by the blooded race; for example, an Ogrish Falchion. Humans cannot be selected as either the chosen race or as a racial enemy. Caster level: 8th; Prerequisites: Craft Magic Arms and Armor, the creator must be of the Blooded race, bestow curse; Market Price: -1 bonus (minimum of 1)
(DM's note: each race has only 2 or 3 "racial enemies" and it's up to the DM to decide who they are before this enchantment comes up. It's a negative Market Price to allow the bad guys to have really powerful weapons that the players can't use, but it's worked well for players as well.)
SLAYER Prerequisite: Blooded. The weapon has been created solely to kill enemies of the Blooded race. When touched by a racial enemy of the Blooded race, the weapon bestows one negative level per round; these negative levels disappear after 24 hours. When used by a member of the Blooded race, the weapon?s Enhancement bonus against racial enemies is increased by 4, the wielder?s AC against racial enemies receives a +2 racial bonus, and any roll to confirm a critical hit against racial enemies receives a +2 bonus. Bows, crossbows, and slings so enchanted bestow this ability on their ammunition. Caster Level: 13th; Prerequisites: Craft Magic Arms and Armor, the creator must be of the Blooded race, harm or disintegrate; Market Price: +3 bonus
for completeness' sake,
PROTECTOR(Armor) Prerequisite: Blooded. The armor has been created to defend against the enemies of the race. When touched by a racial enemy of the Blooded race, the armor bestows one negative level per round; these negative levels disappear after 24 hours. When used by a member of the Blooded race, the armor?s Enhancement bonus against racial enemies is increased by 3, the wearer gains Spell Resistance equal to character level+5 against spells cast by racial enemies, and neutralizes critical hits or sneak attacks by racial enemies 25% of the time. Caster Level: 13th; Prerequisites: Craft Magic Arms and Armor, the creator must be of the Blooded race, globe of invulnerability or greater dispelling; Market Price: +3 bonus
WRAITH The weapon is permanently under the effects of an Improved Invisibility spell, making it extremely difficult to dodge the attacks. Dodge, Haste, Insight, and Dexterity AC bonuses do not count against it. Targets with Uncanny Dodge or who see invisible retain half of their total bonus (round down). Those with both, or who use true seeing, suffer no penalty. Bows, crossbows, and slings cannot be enchanted with this ability. This ability cannot be combined with Brilliant Energy. Caster level: 16th; Prerequisites: Craft Magic Arms and Armor, improved invisibility or amplified invisibility, gaseous form or ectoplasmic form; Market Price: +4 bonus
PUNCTURING The weapon is designed to force its way through mundane defenses. Despite what the name implies, any type of weapon can have this ability. Armor, Natural Armor, and Deflection AC bonuses are cut in half (round down). Bows, crossbows, and slings so enchanted bestow this ability on their ammunition. Caster level: 12th; Prerequisites: Craft Magic Arms and Armor, keen edge or divine power; Market Price: +3 bonus
SERRATED The weapon magically shapes itself to do more damage to vulnerable parts of the target?s body. The critical hit multiplier is increased by 1, and all rolls to confirm a critical hit receive a +2 bonus. Bows, crossbows, and slings so enchanted bestow this ability on their ammunition. Caster level: 8; Prerequisites: Craft Magic Arms and Armor, polymorph self or polymorph other; Market Price: +2 bonus
GREATER FLAMING A Greater Flaming weapon glows orange-red (light source as a torch), as if it were just pulled out of a forge. It deals 2d8 fire damage on a successful hit without the need for a command word; this effect is always on. Anyone struck by such a weapon catches on fire, taking 1d6 fire damage each subsequent round until they can make a Reflex save (DC 15), to put the fire out. Caster Level: 12th; Prerequisites: Craft Magic Arms and Armor, any Fire damaging spell or power of 6th level or higher; Market Price: +3 bonus
There's four others, all with a similar pattern, all with a DC 15 save to avoid a secondary effect: Greater Frost is 2d8 and a Fort save or Slows you for 1 round, Shocking is 2d8 and a Will save or you're Shaken, Sonic is 2d6 and a Fort save or Deafened, Acid is (1d4 for 4 rounds) and Reflex or be Nauseated (as Shaken).
SEARING When placed on a weapon with an Elemental damage bonus, all elemental damage dice increase by one size (d4 goes to d6, d6 goes to d8, d8 goes to d10, d10 goes to d12) and bypass any Elemental Resistance (including from the spells resist elements, protection from elements, or any similar spells or effects). Creatures immune to an element are still unaffected. Caster Level: 6; Prerequisites: Craft Magic Arms and Armor, Greater Magic Weapon; Market Price: +1 bonus
LOADING This ability may only be used on projectile weapons. Instead of the normal loading action, the user can summon a temporary projectile (made either of matter from Shadow or ectoplasm from Astral). The projectile is identical in performance to its mundane cousins with no enhancement bonus. These projectiles break down one minute after being summoned. Weapons with this enchantment are still capable of firing normal ammunition. Caster level: 10th; Prerequisites: Craft Magic Arms and Armor, greater shadow conjuration or major creation; Market Price: +1 bonus