I haven't sold a bike yet, so the answer is- all the ones I grew out of as a kid!
My Raleigh Esquire which I got in 1978 for my birthday, was the best birthday present ever, beyond my wildest expectations- a brand new bike!
Such things were uncommon in Orkney at the time, and me and my pals all went around on tenth-hand bikes, most of which had the lever actuated solid link gear contraptions. I can easily recall the brands, for as kids we loved the badges, and hey we only got BBC1 and Grampian in B&W, we needed colour in our lives- BSA, Sunbeam, Phillips, Hercules and Triumph, and some Raleighs.
The bike I had at the time was 24" wheeled Hercules Jeep, one gear, but modern in that the handlebars did not wrap around, and it had cable operated calipers brakes. Small frame, so quite sporty in appearance compared with the oversize wartime bikes, white mudguards, and a matt black frame finish, with worn gold decals. In fact I think I miss this bike almost more than my Esquire!
The Esquire was a status symbol, and we would pimp our rides with mudflaps, and extra lines on the mudguards made using white or yellow insulating tape cut narrow. For a while I had a braking light on my bike having rigged up a crude switch system on the brakes to operate my Pifco rear light. As the years went by numerous partial resprays took place using Holts Dupli Colour brown metallic paint that was a surprisingly good match.
My pal's Esquire came to a sticky end however, as the front mudguard stay came loose as he hurtled downhill, caught the tyre and proceeded to wrap around the axle, resulting in a horrible prang, a heart shaped wheel and broken forks. Didn't do my pal any good either.
My own one passed into the hands of my dad when I went to university, and he ran it for a while before trading it in for a Raleigh MTB, in a frame size that was slightly too big for me, and far too big for him given I am 4" taller. I bought him an Edinburgh Bike Co-op F+F in the right size, so all is now well.
I found an old (but not as old as my Esquire) catalogue from about 1980, so I can show you the bike in question, although I feel strangely drawn to the Caprice next door. I've also scanned in the Grifter page for Zigzag.
and the Grifter and Chopper page: