Here is a list of Servants with Brynhildr’s Beloved trait. Those servants are weak to Brynhildr's Noble Phantasm, Brynhildr Romantia.
Rashoumon event (Ibaraki Douji event)
Murder at the Kogetsukan
Inheritance of Glory
Best Servants [★4]: 4 Star Tier List
Anne Bonny & Mary Read (Rider)
Berserker - Craft Essences
Ushiwakamaru
Altria Pendragon (Lily)
Passionlip
Chaldean S.I.U.
Ereshkigal
Arthur Pendragon(Prototype)
Gorgon
Black Holy Grail (The Black Grail)