Sometimes folks will post that they can't find this tire size.

What I've seen lately:

Bell Sports Streetster (folding) - available at many big box and some hardware stores
Chengshin C638
Continental City Ride
Innova Cloud Nine - seems to be out of stock everywhere currently
IRC Super Gold - on Amazon Japan but I haven't found any in N.A.
IRC Super Seed - on Amazon Japan but I haven't found any in N.A.
IRC City POPS - on Amazon Japan but I haven't found any in N.A.
Kenda gumwall
Kenda Cross (knobby)
Kenda K40 Street
Michelin World Tour - traditional tan sidewalls
Nutrak Traditional - available from UK shops, but haven't found any in N.A.
Nu-teck (airless)
Panaracer Col de Vie - traditional tan sidewalls
Panaracer Passhunter (light knobby) - sporadically imported in small quantities by Kogswell, Longleaf and Aaron's
Panaracer ST Daily Commuting
Pyramid gumwall
Pyramid Sunlite Hybrid Nimbus
Raleigh Record - available from UK shops, but haven't found any in N.A.
Rubena Flash V66
Schwalbe Delta Cruiser - available in all black, all cream and with traditional tan sidewalls
Schwalbe Marathon
Schwalbe Marathon Plus
Schwalbe Speedway Pro (knobby) - available from UK shops, but haven't found any in N.A.
Specialized TriSport
Vittoria Randonneur - cataloged, but I can't find any in N.A.
Vredestein Perfect Tour
Vredestein Dynamic Tour - cataloged, but I can't find any in N.A.
Vredestein Classic - cataloged, but I can't find any in N.A.

tcs