Timestride

Choose a creature within 30 feet of you. For a willing creature, the target's initiative increases by 1d6. If this increases it to the same value as your own initiative, they act at the end of your turn this round. For a hostile creature,  it must succeed on a Charisma saving throw or have its initiative reduced by 1d6.

This spell's initiative change increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).