For the dressing: Whisk together the mayonnaise, vinegar, honey, salt, and pepper in a large bowl until smooth.
For the slaw: Add the broccoli slaw, broccoli florets, carrots, cabbage, green onions, raisins, and sunflower kernels to the dressing; stir to combine. Cover and refrigerate 1 hour or overnight.
Top with more sunflower kernels just before serving, if you like.
