Here are the possible solutions for they come in last clue
Answer
Clue
Relevancy
xyz
Clue
They come last
They come in last
fads
Clue
They come and they go
Definition
FAD, a hobby or interest that enjoys brief popularity
latherdaysaints
Clue
They are clean when they come marching in?
rockbottom
Clue
With 133, the name of the band whose members appear in the theme answers. (They disbanded in 2012 after raising millions for literacy, but they're reuniting this weekend for one last concert.)
all
Clue
"Come one, come ___!"
Definition
the whole
balihai
Clue
Show tune with the repeated line "Come to me, come to me!"