I thought I would list off a few that I've used, or that I've seen used by others in the rabbit world.
I will be using affiliate links to amazon.com simply because it's easy. You may need to look at your local pet store, or visit amazon.ca to avoid import duties.
I have not used all these tools. My go to is to use my fingers and slightly damp hands. I place my bunnies up on a piece of wood sitting over my compost and run my hands through their fur to remove loose hair, and then pluck whatever they are shedding out. Takes about five minutes every day for about a week and then they are done if they are shedding fast. :)
For rabbits that take their time shedding I pull them out as needed for a quick grooming session.
They also work with longer-furred animals, I find they don't get to the undercoat quite as well as with smooth-coated animals.
Work out any mats carefully. Take your time. Rabbits have a thin skin that can tear easily. Keep your movements short and gentle.