Most useful python modules from the standard library are −
math − Very basic mathematics module
re − Regular expressions module with very powerful functions for text manipulation
datetime − Basic dates and time manipulation library
json − For json to dict conversions, json manipulation, etc.
random − For getting pseudo random variables.
os − For interacting with the operating system
copy − for deep and shallow copying
sqllite3 − for interacting with the light sqllite3 databases
io − for working with streams
multiprocessing and threading − For creating threads/processes
urllib − For handling urls, sending requests, handling responses, etc
http − For creating http servers, manage state, etc
locale − For internationalization of your program