Just a few examples of the type of collars and leads I've found to be good choices for dogs. I haven't desplayed any harnesses due to the high number and varying types and designes available. Some harness types are better than others but as long as the harness fits securely and is comfortable for the dog it doesn't matter too much which type you choose.
The Halti Training Lead is probably my favourite type of lead, it's comfortable and versatile. It comes in small, medium and large. You can wear as a belt or walk two dogs at the same time with one lead.
Padded collars are highly recommended, particularly with a belt buckle type fastener. Try to avoid the plastic clip fastener. You should be able to fit two fingers comfortably under the collar but not three fingers.
There are various types of padded collars with belt buckle type fasteners. Avoid the plastic fasteners, these can let you down when least expected.
Leather padded collars are also available if required. Avoid the plastic fasteners, these can let you down when least expected.
A long line or lung line training lead is ideal for recall training. They can be difficult to use and may become tangled but used correctly they provide security for you while training.
The Dogmatic head collar can be very useful while lead training difficult, strong dogs. They are more comfortable than other head collars and don't tend to ride up into the eyes.
Puppy pens are ideal for puppy training if you don't want to go down the crate training route. Pens are also useful for managing unruly pups.
Puppy pens come in various sizes and shapes, chose one that best suites your circumstances and available room in your home.