The SLD file extension is used to signify slide files in the Autodesk AutoCAD computer-assisted design software program. SLD files can be accessed and edited with the appropriate software.
File extension is used by NEPLAN. Probably older versions (DOS versions).
File extension is used by XnView. File contains slide show created by XnView.
The SLD file extension is associated with Corel Paint Shop Pro, an advanced photo-editing software, developed and sold by Corel Corporation.