Songs your whole group can sing
One range per line, lowest and highest comfortable note, like
A3-E5. Put in everyone who has to sing the same notes at the same
time, and it shows what is left.
Why the list gets short so fast
Everyone singing together is limited by one band, the highest of all the low notes up to the lowest of all the high notes. Each person you add can only narrow it. Two people an octave apart in comfort share almost nothing, however good either of them is.
Take a full choir with all six voice types present, using the reference ranges this site uses everywhere else. The band they share in unison runs from C4 to E4, which is 4 semitones, and 1 song in the catalogue fits inside it.
That number is not a fault in the list. It is the reason choirs sing in parts. If you are picking something for a mixed room to sing in unison, a school assembly or a congregation or a campfire, you are working inside a band of about an octave whether you planned to or not, and this page tells you which octave and what fits in it.
What to do when nothing fits
Three things, in the order that costs least. Allow a few semitones of transposition, which is what the box on the right is for. Drop the one or two people whose range is doing the limiting, named above the table, and let them sing an octave away or take a harmony line. Or split into parts and stop asking everyone for the same notes.
If you do not know everyone's ranges, the range test takes about a minute each in a browser, and there is a write up on running that across a whole choir in one rehearsal.
Where the song ranges come from
Read out of MIDI transcriptions from the Lakh MIDI Dataset, CC BY 4.0, by Colin Raffel, and filtered hard. About a fifth of the songs transcribed twice have versions that disagree by a whole octave, so only songs with two agreeing transcriptions and a range a human voice can produce are here.
Songs in the wrong octave are the remaining defect. I labelled all 214 acts by whether the lead singer is a man or a woman, and the male-led songs came out sitting higher than the female-led ones, which is backwards. The 108 worst are removed rather than shifted. The male half of what is left still runs high on average, so treat a title as a shortlist to check and listen before you hand a song to a room. The single singer version sets out the whole method.