the following is true for NES wizardry and i believe it's true on wizardry on other platforms.each monster category gives a certain category of item. so try fighting a particular category of monster in order to find the good items.
Item Number
78 cursed helmet
79 breast plate +2
80 silver gloves <-- best gauntlets
81 evil sword +3 <-- best weapon for lord (evil)
82 evil ssword +3
83 thieves dagger
84 breast plate +3
85 lords garb <-- best armor for lord
86 muramasa blade <-- best weapon for samurai
87 shuriken <-- best weapon for ninja
88 chain pro fire
89 evil plate +3 <-- best armor for samurai & ninja
90 shield +3 <-- best shield
91 ring of healing <-- best misc item
92 ring pro undead
Category 12 Monsters have 5% chance of giving item 79-92. if you want the (91) ring of healing you should fight these monsters:
frost giant
fire dragon
high priest
high wizard
master thief
hatamoto
vampire
greater demon
poison giant
dragon zombie
Category 13 Monsters has 10% (higher than cat.12 monsters) chance of giving item 78-90. if you want the good items (except ring of healing and ring pro undead) you should fight these monsters:
raver lord
high master
flack
arch mage
maelific
vampire lord
if you have extra shurikens, you should have your first three party members keep one shuriken in the inventory (doesn't need to be equipped except in the case of ninja). shurikens are resistant to level drain and could save your party members from vampires.
although a high level naked ninja may seem invulnerable, it's always better to equip him/her with best equipment. shurikens cause high damage to monster. wearing armor/shield/helm/gauntlets may yield a higher AC than being naked, but in reality a naked ninja with -99 AC is more vulerable to monster attacks than a ninja with -10 AC.