Generic Defensive Gears

Below are noteworthy custom gears applicable to boosting your defense and raw HP. Note that God Items and MVP Cards are excluded from the list.

Aumdura's Grace deserves a second mention for being a slotted accessory with 1 def, while having decent base stats as well
Black Devil Mask is mainly valued for 3 def in mid headgear slot, and its secondary effect is a nice bonus
Luxury Hat is one of the best raw def equipment in the entire game and should be grinded for highest refine possible for tanking characters
Purifier is unique where it's a great defensive gear even though it has low base DEF, due to its unique ability to remove Critical Wound, which is crucial against certain bosses
Ribbon Of Life offers good reductions while still having 1 def in mid headgear slot which is generally hard to fill
Shaman Hat is useful for its resistance if you want to stack resistance of a certain element to 100% or higher
Silver Guard is a shield with niche cases where it provides generic reduction against small targets
Yellow Bandana and Yellow Hairband are great headgear options to build a long range resist gearset

Defensive Cards

Applering Card doesn't give defense but 2 Applering cards can make apple a very cheap but efficient source of healing
Arc Elder Card at +9 is the only way to get both freeze and stone curse immunity while being allowed to be resurrected in party gameplay
Armor Bug Card in accessory can get an unparalleled 4 defense possible in accessory slot
Big Bell Card has a niche if you are building a magic reflect build
Fallen Druid Card can be kept at low refine to get more HP
Abysmal Raydric Card is a balance of having mostly Raydric card effect but also provide HP, which can be more useful than traditional Raydric in some builds