| cmp | Package cmp provides types and functions related to comparing ordered values. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| slices | Package slices defines various functions useful with slices of any type. |
| strconv | Package strconv implements conversions to and from string representations of basic data types. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |
| sync/atomic | Package atomic provides low-level atomic memory primitives useful for implementing synchronization algorithms. |
| unicode | Package unicode provides data and functions to test some properties of Unicode code points. |
| unicode/utf8 | Package utf8 implements functions and constants to support text encoded in UTF-8. |