Booming blade is stupid
Booming Blade is a new cantrip, but because it uses a weapon attack roll, it qualifies for Extra Attack, since it's a cantrip, it has several powerful synergies, maybe even too powerful:
Ring of Elemental Infusion will add 1d4 thunder dmg on every attack;
Ring of Arcane Synergy will allow you to have Arcane Synergy) for 2 turns after you deal damage with a Cantrip, a replacement of Diadem of Arcane Synergy for headwear and can use something else like Birthright or Helmet of Arcane Acuity;
Quickspell Gloves will allow you to do an extra attack with your main weapon for the cost of a bonus action;
Necklace of Elemental Augmentation for extra dmg equal to your spellcasting Modifier;
Boots of Elemental Momentum to gain momentum after you cast a cantrip;
Potent Robe for extra dmg equal to your charisma Modifier;
Hat of Storm Scion's Power for Arcane Acuity) when you deal thunder damage.
Ring of Absolute Force: If the wearer bears the Absolute's Brand, they deal 1 additional Thunder with thunder damage spells and attacks.
Markoheshkir's Bone-shaking Thunder will add additional thunder damage to your spells equal to your proficiency bonus.
The reverberation condition) as a whole, and its equipments.