linecache, xml, wave • db: sqlite3, dbm • Network: socket, ssl, async • Web: urllib, http.server, email, ftplib, cgi, html, uu • Crypto: hashlib, hmac, secrets • Software: logging, unittest, mock, doctest, curses, sched, queue, getpass, gettext, tk,pdb, profiler • Concurrency: threading, multiprocessing, async, futures, subprocess • collections, functools, itertools… Python docs