| database/sql | Package sql provides a generic interface around SQL (or SQL-like) databases. |
| database/sql/driver | Package driver defines interfaces to be implemented by database drivers as used by package sql. |
| encoding/json | Package json implements encoding and decoding of JSON as defined in RFC 7159. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| math | Package math provides basic constants and mathematical functions. |
| reflect | Package reflect implements run-time reflection, allowing a program to manipulate objects with arbitrary types. |
| time | Package time provides functionality for measuring and displaying time. |