SLK file is a Symbolic Link Spreadsheet. Symbolic Link (SYLK) is a Microsoft file format typically used to exchange data between applications, specifically spreadsheets.

Common .slk file type descriptions:

Microsoft Excel-SLK-Datenimportformat
Microsoft Excel SLK Data Import Format
Microsoft Office Excel SLK Data Import Format
OpenOffice.org 1.1 Spreadsheet
Формат импорта данных Microsoft Excel SLK

Applications, associated with .slk files

	Microsoft Office Excel by Microsoft Corporation
	LibreOffice Calc by The Document Foundation
	OpenOffice.org Calc by OpenOffice.org
	OpenOffice Calc by Apache Software Foundation
	PlanMaker by SoftMaker Software GmbH

.slg

.sln