Here is the complete list of SAP Tables in KM module. The most commonly used Tables are at the top of the list.

Table Description
IWEXTSYMBT KEn: Html Export Text Symbols
IWEXTSYMBS KEn: Html Export Text Symbols
CUSTNODE Node Table for General Structure Storage
CUSTPHIO KW: Instances of Physical Information Objects
CUSTLOIO KEN: Instances of Logical Information Objects
CUSTLORE KEN: Outgoing Links of Logical Information Objects
CUSTLORI KW: Incoming Links of Physical Information Objects
CUSTPHHR KW: Outgoing Hyperlinks from Physical Objects
CUSTPHNM KW: Use of Target Anchors in Physical Objects
CUSTPHRE KW: Outgoing Links of Physical Information Objects
CUSTPHRI KW: Incoming Links of Physical Information Objects
IWREFERENC IWB: Info Object Where-Used References
CUSTIDXSTA SDOK: Status Table for Indexing Documents: IWB1
CUSTLOPR KEN: Attributes of Logical Information Objects
CUSTNODER General Structure Storage References