B&W Film Developer
Black and White Film developers vary widely in price, style and environmental impact, so please read all instructions carefully and do take care when handling and disposing.
Universal style developers like the Ilfosol, Fomadon or the FD10 are good bets for no fuss processing.
One shot developers are convenient but obviously more expensive and as they are not meant to be re-used they de facto have a greater environmental impact. Bear in mind that many so called one shot devs can in fact be re-used.
Powders are convenient for storage and often offer the best type of processing, but they require making up time.
Some developers are aimed specifically at finer grain film etc.
Bear in mind that chemistry can be mixed and matched across brands: you do not need to use a fix of the same brand as the dev for example.