tag-rag and bobtail

An expression meaning an assemblage of low people, the mobility of all sorts.

Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.

Although I tend to know it as rag tag rather than tag-rag

I guess raggle taggle comes from the same source. The rag part "may" refer to trading in rags as in rag and bone men.