How do you find out about cool new packages? Reddit suggests /r/emacs, emacs.zeef.com, Paradox or package-list-packages, @melpa_emacs, Emacs-related blogs, gnu.emacs.sources, rubikitch’s feed, the MELPA repository (also available as a feed), Emacsist, Awesome Emacs, and other sources. ericjmritz has also been posting overviews of recently released/updated Emacs packages together with suggested config and other resources. September features: eno or avy for navigation, modalka for modal editing, nameless for namespaces, and highlight-thing for seeing other instances of a keyword under point.)

Quite a few people posted navigation tweaks. Check out these Hydra-related blog posts about Paradox, navigation, and other packages. If you use isearch a lot, swiper might be a faster way to search (it now supports visual-line-mode too), and you might like this multiple-cursors extension for it too. Multiple-cursors is neat.

There were a couple of writing-related resources, too. Emacs for Writers was a talk by Jay Dixit at the New York Emacs Meetup. Also, /u/yamadpc asked about a focused mode for writing. Suggestions included focus, darkroom-mode, writeroom-mode, and olivetti. In terms of building your own from the ground up, Emacs, naked describes variables you can set and functions you can call in order to make your Emacs screen cleaner.

Coding:

• An update for the Buttercup Emacs Lisp behavior-driven testing framework has been released.
• Want to run some Emacs Lisp code when a file changes? Use filenotify.
• To wrap text in other text (ex: Org mode markup, HTML tags), consider using wrap-region.
• Need to automatically update a timestamp in your text file? Reddit suggests header2.el or time-stamp.el.
• fniessen/emacs-leuven has a lot of Org agenda custom commands.

Videos:

• How to organize your config with Org Mode and use-package (part 1, part 2)
• Emacs for Writers (1:01:06)
• 2015-10-14 Emacs Hangout (1:20:51)
• Emacs.el Episode 2: Samer Masterson (0:38:10) chatting about the Emacs conference, Eshell, and the Emacs community
• Setup your erlang environment with emakefile, .erlang and .emacs: Emacs bit starts around 3:14.
• Web search from the Emacs (0:06:48): keyword-search
• M-x remember (0:03:21) Saving quick notes to a ~/.notes file
• follow-mode (0:02:11) Scrolling windows
• emacs + R (0:00:24) Quick demonstration of transforming text and running R on it.
• emacs + postscript (0:01:13): Writing Postscript by hand.

Also, just for fun: Pacman.

Links from planet.emacsen.org, reddit.com/r/emacs, Youtube.