Best shields:
88 stability - Greatshield of Artorias ( no upgrades needed to achieve this level of protection once made; requires a +10 Tower Shield along with Sif's Soul)
85 stability - Hollow Soldier's Shield ( +15/requires a Titanite Slab)
84 stability - Eagle Shield ( +15/requires a Titanite Slab)
84 stability - Havel's Greatshield ( requires 50 strength to wield/no upgrades needed/great resistances to magic, fire, and lightning)
83 stability - Silver Knight Shield (+5/requires 10 twinkling titanites)
Niche shields:
Black Knight Shield - 95% Fire Reduction
Crest Shield - 80% Magic Reduction
Grass Crest Shield - Stamina Regen
Sanctus - HP Regen in a pinch
Crystal Ring Shield - BFG
88 stability - Greatshield of Artorias ( no upgrades needed to achieve this level of protection once made; requires a +10 Tower Shield along with Sif's Soul)
85 stability - Hollow Soldier's Shield ( +15/requires a Titanite Slab)
84 stability - Eagle Shield ( +15/requires a Titanite Slab)
84 stability - Havel's Greatshield ( requires 50 strength to wield/no upgrades needed/great resistances to magic, fire, and lightning)
83 stability - Silver Knight Shield (+5/requires 10 twinkling titanites)
Niche shields:
Black Knight Shield - 95% Fire Reduction
Crest Shield - 80% Magic Reduction
Grass Crest Shield - Stamina Regen
Sanctus - HP Regen in a pinch
Crystal Ring Shield - BFG