Unarc unpacks an archive and creates a top-level directory to unpack into if it's needed. Unarc works with lots of archives, not just tarballs (bz2, zip, and even rpm are supported). There is a companion program arcdir which provides a uniform way to archive directories into tarfiles, zipfiles, etc.
uncsv is a filter command converting the lines of a CSV file into a non‐escaped, non‐quoted delimited file (pipe by default). csv is the opposite of this command; it takes an un-quoted stream of values, separated by the delimiter of your choice (default: pipe ’|’) and produces a "standard" CSV file. Both tools avoid end‐of‐line character politics and will leave these untouched.
Unifdef is useful for removing #ifdef'ed lines from a file while otherwise leaving the file alone. You specify which symbols are defined or undefined with -D and -U flags, and unifdef removes the corresponding ifdefs, and the enclosed code if appropriate. It's especially useful for removing those "#ifdef BROKEN" and "#ifdef PRIVATE" clauses from code before you release it. Unifdef acts on #if, #ifdef, #ifndef, #elif, #else, and #endif lines, and it knows only enough about C and C++ to know when one of these is inactive because it is inside a comment or a single or double quote.