Steam Exclusive Starter Kit
The Steam Exclusive Starter Kit can be purchased via Steam for $19.99. You do not require Neverwinter to be installed via Steam to purchase the pack, though a Steam account will of course be required for the transaction.
The kit can be applied to an account by following the instructions for redeeming codes in the Arc client. The kit will then be available for a single claim on the Claim tab of the Reward Claims Agent in Protector's Enclave.
WARNING: Only the first instance of the code for this kit applied to an account will provide a reward, and further codes gained and applied (for instance from a second Steam account) will be wasted.