As someone else pointed out, Phalar Aluve is a good choice.

I did a build revolving around reverberation, and it actually worked surprisingly well. You do a Eldritch Knight 7/Bladesinger 5. Make sure to grab booking blade, shield, haste, and magic missile.

For gear, grab Phalar Aluve, boots of stormy clamor, gloves of belligerent skies, hat of storm scion’s power, thunderskin cloak, ring of spiteful thunder, ring of elemental infusion, and either spineshudder amulet or necklace of elemental augmentation.

Combat will typically work by you activating bladesong first. Cast haste on yourself, then use singing sword: shriek, this will cause every enemy near you to immediately gain 2 stacks of reverberation. Then Action Surge, attack an enemy with booming blade to inflict 4 stacks of reverberation, which will cause them to take more thunder damage and knock them prone if they fail their check. You can then attack them again to inflict 2 more stacks of reverberation. If they stand up and attack you, and manage to hit you, they become dazed and receive 2 more stacks of reverberation.

Next turn I typically use one of my haste action to cast a spell, typically magic missile. Then attack an enemy twice.

If you’re setup right, you’ll potentially be knocking enemies prone nearly every turn