At one time a notice appeared on MMD saying that a list of compositions
by Carl Frei would be added to the MMD Archives.  I have not found that
list.

Through INTERNET searches I have found listings of a number of titles.

A Dutch WIKI includes the information below. I have used Google
Translate to provide an approximate English version.

  http://nl.wikipedia.org/wiki/Carl_Frei 

Composities - Compositions

Hieronder enkele stukken die door Carl Frei gecomponeerd en
gearrangeerd werden:  Some pieces composed and arranged by
Carl Frei are:

Hommersonmars - Hommerson March
Spaanse Ruitermars - Spanish Riding March
Gouden Hartserenade - Gold Heart Serenade
Raupenbahnmars - Raupenbahn March
Cara Miawals - Cara Mia Waltz
Friedrichsmars - Friedrich March
Aubadewalzer - Aubade Waltz
Oranjemars - Orange March
Verboden Wals - Forbidden Waltz
Liefdesdroom Serenade - Dream Love Serenade
Vredesbondmars - Peace Bond March
Bella Isabel  - Beautiful Isabel
De Negentigermars - The Nineteenth March or possibly
  19th Regiment/Brigade/District March
Vrolijke Muzikantenwals - Merry Musicians Waltz
Serenade Nr. 1. - Serenade No. 1.
Goudamars - Gouda March

Erik Kluver's website - Muziek - Gegevensbank van MIDI-bestanden -
includes four MIDI files attributed to Carl Frei:

  http://members.chello.nl/f.kluver/muziekmi.htm 

Fanfare Mars - Fanfare March
Komet Marsch - Comet March
Jo-jo wals - Jo-Jo Waltz or maybe Yo-Yo Waltz
Step - Step (March)

A discography lists the following additional titles:

  http://www.45cat.com/45_composer.php?tc=Carl+Frei 

Al Banico -
Molto Vivace -
Odeon Mars - Odeon March

Wallace Venable