| database/sql | Package sql provides a generic interface around SQL (or SQL-like) databases. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| math/rand | Package rand implements pseudo-random number generators suitable for tasks such as simulation, but it should not be used for security-sensitive work. |
| regexp | Package regexp implements regular expression search. |
| 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. |
| testing | Package testing provides support for automated testing of Go packages. |
| time | Package time provides functionality for measuring and displaying time. |