Compared to the best weapons and accessories, it takes a lot less effort to get the best armor, but it requires a bit more luck. To have the best armor for your whole party will require at least 2 playthroughs.
To access the shady commodity site, you’ll need to buy a broken laptop from the second hand store in Yongen Jaya in September and the PC tool set from the old machine parts store in Akihabara. Then repair it at your work bench at home. You’ll have to spend 100k Yen by 12/11 on the shady commodity store before you can buy the unwashed “Desecrated Gear and the Unholy Armor.”
The laundromat armor is determined when you wash, not when you pick them up, so save before the item is washed, if you don’t get what you want just reload the game.
Men
Tantric Oath – 272 Def, 18 Evasion, +Reduce Magic dmg (high) – You can make multiples of this by itemizing Satan (Max Judgment Confidant) with a Black Robe. This can be expensive depending on your level.
Karna’s Robe+ – 273 Defense, 20 Evasion, +Reduce Physical dmg (med) – You can start buying Desecrated Gear from Tanaka’s Shady Commodities website starting 12/11.
Demon’s Jacket+ – 304 Defense, 21 Evasion, Strength +5) – You can start buying Unholy Armor from Tanaka’s Shady Commodities website starting 12/11.
Women
Haten Robe+ – 275 Defense, 25 Evasion, Magic +5 – Unfortunately there aren’t any options for women’s armor if you want high defense. You can start buying Unholy Armor from Tanaka’s Shady Commodities website starting 12/11.
Morgana
Nekomata Coat+ – 287 Defense, 29 Evasion, +Evade Psy (high) – You can start buying Unholy Armor from Tanaka’s Shady Commodities website starting 12/11.