The only sharks that will benefit from remoras are larger requiem sharks. The remoras will remove parasites and clean up food scraps. For sharks typically kept and suited for home aquaria (bamboos, epaulettes, horns, catsharks, etc.) the remoras will prove to be a nuisance. They tend to be much more aggressive eating and can outcompete the sharks for food. They also grow much faster than the sharks and add significant bioload to your tank.
Remoras are very interesting and unique fish in their own right, but I would not keep them with the intention of "helping" your sharks.