There is a total of 6423 clues beginning with op
- Open fabric
 - Open favorite
 - Open field
 - Open fields
 - Open fighting
 - Open fire in a fireplace
 - Open fire item
 - Open fire on
 - Open fire on a hearth
 - Open fire roasters
 - Open fire, perhaps
 - Open fireplace
 - OPEN FLOOR PLAN!
 - Open footwear
 - Open for all to see
 - Open for Christmas
 - Open for discussion
 - Open forest areas
 - Open forest space
 - Open forest spaces
 - Open formally
 - Open forum on Reddit: Abbr
 - Open freight cars
 - Open from a rolled-up position
 - Open fruit pie
 - Open G and standard
 - Open galleries
 - Open gallery
 - Open gallery
 - Open garage
 - Open gems
 - Open grassland
 - Open grassland in Africa
 - Open grasslands
 - Open grating
 - Open grazing area
 - Open grazing land
 - Open ground
 - Open grounds
 - Open handbag
 - Open hastily
 - Open hearing, in law
 - Open hearings in courts
 - Open horse-drawn carriages
 - Open hostilities
 - Open hotel lobbies
 - Open house
 - Open House in real estate
 - Open house events
 - Open house features, at times?
 - Open house host
 - Open house initials
 - Open house invitation
 - Open house offering
 - Open house org
 - Open house organizer
 - Open house, eg
 - Open house, perhaps
 - Open house?
 - Open in a way
 - Open in astonishment
 - Open in the garden
 - Open in weave
 - Open indelicately
 - Open inner courtyards
 - Open insults
 - Open Inuit boats
 - Open investigation?
 - Open invitations from puzzle people?
 - Open just a bit
 - Open just a crack
 - Open just a little
 - Open just a tad
 - Open just barely
 - Open kimono preventer
 - Open land
 - Open land for an eland
 - Open lands in Africa
 - Open like an oyster
 - Open line indicator
 - Open litter of Japan
 - Open living rooms
 - Open living spaces
 - Open locale
 - Open love?
 - Open mall areas
 - Open materials
 - Open meadow
 - Open meadows
 - Open mic night figure
 - Open mic night participant
 - Open mic night participant, eg
 - Open mic night performers, often
 - Open mic offering
 - Open mic performer, often
 - Open mike goof
 - Open mike night format, perhaps
 - Open mike night participant
 - Open mike night participants
 - Open military conflicts