PDW, Planet Bike and Blackburn are good brands of aftermarket bicycle taillights, according to Gizmodo. Products offered by these manufacturers include the PDW Danger Zone, Planet Bike Superflash Turbo and the Blackburn Mars 4.0.
The PDW Danger Zone is a battery-operated aftermarket taillight with twin bulbs and several strobe settings. It operates for 27 hours per battery change and weighs 56 grams.
The Planet Bike Superflash Turbo is a bright taillight with a fast, random strobe pattern. It has a rigid plastic housing and fits in all Planet Bike taillight mounts.
The Blackburn Mars 4.0 offers solid and flashing light modes. It comes with a lightweight plastic mount that installs without tools.