Most standard panniers will fit on the Blix rear rack. We are also launching our own line of bags that fit the Blix bikes.
We recommend visiting your nearest Blix dealer (or other local bike shop) where you can mount various options to your rack to check the fit, as well as compare features and options.
For year-round, all weather commuting, Ortlieb panniers are a great choice. Other good brands include Axiom, Arkel, Banjo Brothers and many others.