Um'ed Guardian Angel

[Kartoffelsalat]

I think this is all the uniques that add + to max resists:

Nokozan Relic (amulet): +10% max fire resist
Spirit Keeper (earth spirit): +10% max poison resist
Dragonscale (zakarum shield): +5% max fire resist
Darkglow (ring mail): +5% max all resist
Hawkmail (scale mail): +15% max cold resist
Venom Ward (breast plate): +15% max posion resist
Hotspur (boots): +15% max fire resist
Hellcast (heavy crossbow): +15% max fire resist
The Jade Tan Do (kris): +20% max poison resist
The Tannr Gorerod (pike): +15% max fire resist
Guardian Angel (templar coat): +15% max all resist
Venom Grips (demonhide gloves): +5% max poison resist
Infernostride (demonhide boots): +10% max fire resist
Waterwalk (sharkskin boots): +5% max fire resist
Snowclash (battle belt): +15% max cold resist
Thundergod's Vigor (war belt): +10% max lightning resist
Coldkill (hatchet): +15% max cold resist
Hexfire (shamshir): +10% max fire resist
Cloudcrack (gothic sword): +10% max lightning resist
Andariel's Visage (demonhead): +10% max poison resist
Rune Master (ettin axe): +5% max cold resist

EDIT: Edited to include Hawkmail