Quite a few of the entries in the DT database don't have tunes because they're not songs - they're monologues or similar non-sung pieces. A quick trawl has revealed the following but there may be more:

ALBLION - ALBERT AND THE LION
ALBLION2 - ALBERT'S RETURN
ALBERTRE - ALBERT'S REUNION
AMPIE2 - AMERICAN PIE--PROGRAM NOTES
BTTLHAST - BATTLE OF 'ASTINGS, THE
BATTHAST - BATTLE OF HASTINGS, THE
WORKHOUS - CHRISTMAS EVE IN THE WORKHOUSE
DECKCARD - DECK OF CARDS
DEEDNTAL - DEED OF ENTAIL
EILAROO.NOT - EILEEN AROON NOTES
ESKNELL - ESKIMO NELL (Amalgamated)
GRNWALE.NOT- GRANNY WALE NOTES
GRNRUSH4 - GREEN GROW THE RUSHES (COMMENTARY):
JUBSOV - JUBILEE SOVEREIGN
LRYGRGN.NOT - LARRY GROGAN NOTES
FYVINOTE - Notes for Bonnie Lass of Fyvio/Peggy of Darby/
SAMSMLLM - SAM, SAM, PICK UP THA MUSKET
XMASPDNG - SAM SMALL'S CHRISTMAS PUDDING
HAPNCEFTAL - THREE HA'PENCE A FOOT

Then there are plenty where the tune are in the DT, but another song or version. For instance yesterday I posted the ABC for The Fireship, but now I find it's also there as [FIRESHI2 The Roving Kind. So one tune kills two blanks. Likewise I sent Dick the tune for Beauty of Kashmir, but it's also in DT as [ROBBERS Come Fill Up Your Glasses, and as [CNDLFRD The Candleford Anthem, and Off to Dublin in the Green is also [JOLLPLO3 The Ploughboy (Warwickshire RHA) and [DUBLNGRN The Merry Ploughboy

And there are 16 variants of Streets of Laredo in the DT with no tune listed - but the tune is already there:
LAREDS11 - THE BAD GIRL'S LAMENT
LAREDST6 - THE BALLAD OF BLOODY THURSDAY
LAREDS14 - THE GIRL IN THE DILGER CASE
LAREDS17 - I ONCE WAS A CARMAN IN THE BIG MOUNTAIN CON
LAREDS18 - THE LINEMAN'S HYMN
LAREDS10 - NOO I'M A YOUNG MAN CUT DOWN IN MY PRIME
LAREDS12 - ONE MORNING IN MAY
LAREDST9 - PILLS OF WHITE MERCURY
LAREDS16 - ST. JAMES HOSPITAL
LAREDS15 - THE STREETS OF LOREDO
LAREDS20 - A SUN VALLEY SONG
LAREDST7 - THE TROOPER CUT DOWN IN HIS PRIME
LAREDST5 - THE UNFORTUNATE RAKE
LAREDS19 - THE WILD LUMBERJACK
LAREDST8 - THE YOUNG SAILOR CUT DOWN IN HIS PRIME
YNGMNPRM - YOUNG SAILOR CUT DOWN IN HIS PRIME

There must be many more, especially parodies, where the tune is already there but not linked to the song in question

Finally, although the tune is originally English, I feel it should be a US 'Catter who posts the tune for [STARSPAN THE STAR SPANGLED BANNER, which will also clear up these two [ANACRON2 ANACREONTIC SONG (2), and [ANCREON TO ANACREON IN HEAVEN

Wassail! V