Monk related item enchantments has a list of useful stuff. some highlights:
- Pendant of the Red Abishai (ml 5) is the lowest level item with enhanced ki, which is very (ahem) key
- Jidz Tet'ka (ml 5) is nice, even if only as a swap. Particularly, it gives +10 insight jump in wind stance and +50 insight heal amp in fire.
- Perfect Pinnacle (ml 10) has reinforced fists (an extra half damage die unarmed), has deadly and stunning bonuses, and like the jidz-tetka, has different benefits in each stance (best is probably air which gives you 3d6 elec dmg and a bleed dot on hit)
- Moonrise Bracers (ml 15) has reinforced fists, enh ki, +16 concentration, and when you use your 3x light heal finisher, you gain 5 melee power and hamp for 10 sec
Any other items that are generally good for melee also apply.
Assuming you take the stunning fist feat, items that boost your stun DC (stunning, dazing, and combat mastery) are nice.
Your stable ki is based on your concentration, so the more the better.
You become uncentered if you reach medium encumbrance, so make sure to equip strength items even if not str based.
Monks get evasion, so you gain a lot of benefit from having a high reflex save.