There are two basic valance types for vertical blinds, the channel panel and dust cover valances. These act as a fascia to cover the headrail
GMA Group Vertical Blind Dust Cover Valance Clip Holder Bracket Plastic clips for window blind - White, Pack of 4
A Guide To Placing Your Curtains Over Blinds – Furnishing Tips
TailorView 3 1/4H Faux Wood Crown Valance
Vertical Blind Straight Panel Valance Clip (1-15/16 Inch Headrail)
How to Hang Curtains Over Blinds
A DIY Guide for Fixing Bent Vertical Blinds
Graber Vertical Blind G71 Valance Clip (1-7/8 Inch Headrail)
Symple Stuff Room Darkening Vertical Blind & Reviews
Vertical Blinds Vertical Window & Door Blinds - Blinds To Go