Augment Familiar

You touch your familiar and empower it, making it quicker and stronger. You can also target a Small or Tiny beast of CR 1/8 or lower that isn't a polymorphed or shape-shifted creature, such as a pet mouse or a Cat. 

The creature's Speed increases by 10 for the duration, and it gains 10 Temporary Hit Points. It has Advantage on Strength, Dexterity, and Constitution saving throws, and Resistance to Bludgeoning, Piercing, and Slashing damage. If the target is your familiar, it also gains additional benefits, based on its creature type (see table below).

Using a Higher-Level Spell Slot. The number of Temporary Hit Points increases by 5 for each spell slot level above 2. You can choose to make your familiar one size larger and more vicious. When you take the Attack action, you can forgo one of your own attacks to allow your familiar to make one attack with its Reaction. The attack deals an extra 1d4 damage of its natural weapon type (Bludgeoning, Piercing, or Slashing).