We stock wagons from several ranges, always a random selection and often ones at bargain prices. In general you can mix different wagons on a train as it was always rare (at least in the steam era) to run a single train with just one company's wagons on it. The ranges are as follows:
Hornby: These are full detail wagons, correctly scaled and with accurate logos, liveries and running numbers.
Hornby Railroad: These are older Hornby designs, often a little larger and are the wagons typically included in train sets. These tend to be what Hornby produced as "standard range" around 20 years ago.
Bachmann: These are very highly detailed, good quality wagons with accurate scale details. Licensed liveries are used in many cases.
Oxford: These are halfway between Hornby and Railroad in detail but tend to be very good value.
All brands have similar couplings and will usually pull each other - so can be mixed on a train.