Here is a Z80 version of  Ward Christensen's RESOURCE.COM. It's called REZ.
The Original documentation on the CP/M-CD applies.

The only differences are:
 
 -- support for all 7## original Zilog(r) mnemonics
 -- automatically generated Labels
 -- first letter depending on sort: "c" for CALL, "r" for relative jump etc.
 -- first letter in lower case, so they sort after hand-input one's
 -- a little bit larger :-(
 -- but no "naughty, aren't you" - message

No source, as in the original...

Enjoy.....