| aav.d | An associative array implementation |
| array.d | A dynamic array implementation |
| bitarray.d | A compact array of bits |
| complex.d | A complex number type |
| ctfloat.d | A floating point type for compile-time calculations |
| env.d | Modify environment variables |
| file.d | Read a file from disk and store it in memory |
| filename.d | Encapsulate path and file names |
| hash.d | Calculate a hash for a byte array |
| longdouble.d | 80-bit floating point number implementation in case they are not natively supported |
| man.d | Opens an online manual page |
| optional.d | Implementation of an ‘Optional’ type |
| port.d | Portable routines for functions that have different implementations on different platforms |
| region.d | A region allocator |
| response.d | Parse command line arguments from response files |
| rmem.d | Allocate memory using malloc or the GC depending on the configuration |
| rootobject.d | A root object that classes in dmd inherit from |
| speller.d | Try to detect typos in identifiers |
| string.d | Various string related functions |
| stringtable.d | Specialized associative array with string keys stored in a variable length structure |
| strtold.d | D implementation of the standard C function strtold (String to long double) |
| utf.d | Encoding/decoding Unicode text |
