A SDMB Staff Report on Mack the Knife says, "So in 1927 … Brecht wrote or adapted the lyrics, and Weill wrote or adapted the music. Gay’s eighteenth-century ballads were replaced with foxtrots and tangos.
I’ve heard of foxtrots but have no idea what characterizes them.
Are there song titles I would recognize, or is it just an instumental form?
Hi Limbo Donni
The definition of a foxtrot, if it helps, is: a ballroom dance in quadruple time; combines short and long and fast and slow steps fixed sequences
A list that you can listen to is here.
A longer list.
Generally speaking, foxtrot music is in 4/4 time with accent on 1 and 3. It’s a happy, slightly bouncy dance. Please consider dropping “dance foxtrot” into amazon.com or “foxtrot dance music” into google.com.
Thanks Daizy. That was just what I’m looking for.
(The Devil’s Grandmother - If you don’t like to see questions asked and answered on message boards, instead of web searches, you’ve come to the wrong place. IMHO)
“Classic” foxtrot songs are those from the Big Band Era and just about anything from Frank Sinatra. More recently, much of Harry Connick, Jr’s songs (big band) fall into this category too.
As others have said, it is in 4/4 time, the basic steps much like the box waltz except for the timing. (Slow, quick quick, slow…)
You’re most welcome Limbo Donni
I’m sure The Devil’s Grandmother didn’t mean their post the way you may have taken it. I’m sure they just meant that you’d find foxtrot songs just by typing the word “foxtrot” into your favourite search engine. That’s how I found those lists for you. I knew a couple, but was drawing a blank for others. 
The majority of 78’s that were popular music were marked as “foxtrots” - including some pressings of Bill Haley’s “Rock Around the Clock.”
4/4 time with beats on the 1 and 3 is a very common song framework.
All I’ll add is that it needs to be 4/4 swing timing. Straight timing won’t work for foxtrot. Any 4/4 medium-tempo swing music will work for foxtrot. As said before, medium tempo big band jazz is best for foxtrot.
Yep … my wife and I foxtrotted to “It Had to Be You” for our wedding dance.