Findings:

• sdd (user)
• Spybot S&D (node_forward)
• Mercedes-Benz 300 SD
• SD Snatcher
• Panzerkampfwagen I Ausf B (Sd Kfz 101)
• Panzerkampfwagen 1 Ausf (Sd Kfz 101)
• SD Gundam
• sds (user)
• SDS
• SD Alcohol
• Deadwood, South Dakota
• SD Card
• sd (user)
• Tennents SD
• Mitchell, South Dakota
• Pierre, South Dakota
• SD

If you Log in you could create a ".SD" node. If you don't already have an account, you can register here.