Keiko appears (sings/talks) in the following miscellaneous CDs.

1997 09.01	Next King -Koi no Sennen Oukoku- Gaiden (SRCL-4031)	Talk
1999 06.09	Tom Sawyer no Bouken (TOCT-10614)	Song
2005 11.25	Air Drama CD vol 7 Summer (FCCP-15)	Talk