As a huge fan of S&B builds I recently looked at all legendary shields raw damage and realized that there are no legendary shields only dealing fire damage. There are multiple shields that deal elemental damage, and nearly at least one shield per main damage type (minus fire; and also piercing, but that may be understandable).
In general, legendary shields choices for fire melee Demolitionist are kinda lacking: Wrathguard, Watcher of Erulan and Stronghold are ranged-based, Turrion is weird, and Skybreach is for lightning builds.
Moreover, legendary/MI shields are also lacking modifiers for Demolitionist skills (the only one being Turrion’s ret dmg modifier for Blackwater Cocktail).