Generic Caster Gears

Below are noteworthy custom gears applicable to boosting magical damage output. Note that God Items and MVP Cards are excluded from the list.<be>

Balloon Hat is a cheap option to get decent MATK while having a slot on your headgear
Bradium Earring is good generic accessory with INT and MATK % bonus, usable by all classes
Dreamstone Charm is weaker than Menacing Doll but has no downside of generic ATK/MATK boost
Lounge Suit is an option when defense is not a concern, and you want to attack/cast faster while having a card slot, though armor with 3 dex may help most players more for cast speed.
Koneko Cat is a decent generic caster headgear if you do not have any choice of cards for headgear
Magic Quartet is one of the best offensive accessories giving 4 INT in accessory and can be comboed with lv 1 bolts for one of the best AoE magic boost, but it is from an endgame MVP dungeon
Magical Booster is a good generic mid headgear slot for casters
Menacing Doll offers good boosts while keeping a card slot, but it can be a drain on your resource to maintain it
Purple Cowboy Hat is one of the best headgear for having 2 int and still having a slot, while taking only upper headgear slot
Time Magician Robe is a solid option for any single target spellcaster, especially for Waterball Wizard. Downside is that it's from one of the hardest dungeon available in heRO so it can be hard to get and is pricy.

Survivor Combo Expanded

Circlet of Survival can be built upon the official Survivor's Rod combos to further grant defensive options along with unbreakable cast in headgear slot so you do not need to swap back and forth with Phen accessory, nor do you need to use Orlean's Gown which has weak stats and slows down your cast time.

Caster Cards

Baba Yaga Card gives 4 INT at the sacrifice of 2 DEX which may be worth the trade for sheer power
Chipmunk Card is good for hybrid builds but casters find that the 25 STR investment is generally worth it for even pure casters