Below is a list of manufacturers of kit used by League One Clubs:
Adidas: Peterborough
Bukta: Millwall
Carlotti: Oldham, Scunthorpe
Diadora: Stockport
Errea: Brighton, Bristol Rovers, Cheltenham
Jako: Leicester
Le Coq Sportif: Carlisle
Lotto: Crewe, Swindon
Macron: Leeds
Mitre: Huddersfield
Nike: Hartlepool, Hereford United, Milton Keynes Dons, Southend
Puma: Colchester, Leyton Orient
Swift: Walsall
Vandanel: Northampton, Tranmere, Yeovil
(List from www.spaotp.com - who have compiled a list for all the top clubs with some information on the makers)