Added February 2014: As I no longer have time to keep both posts updated, all further updates will be made to the version of this post hosted on my personal blog.

In a recent post, Qiaochu Yuan noted that "various mnemonic techniques like memory palaces, along with spaced repetition, seem to more or less solve the problem of memorization." The list below is an attempt to compile all existing Anki decks created by Less Wrong users, in the hope that they will be of help to others in memorizing the corresponding material. (Anki is arguably the most popular spaced repetition software.)  If you know of a deck not included here, please mention it in the comments section and I'll add it to the list. Thanks!

Accounting and Finance

• Ivo Welch's Corporate Finance (2nd ed.) (in progress), by Pablo_Stafforini.
• Mark Piper's Accounting Made Simple, by Pablo_Stafforini.

Art and Music

• 100 Greatest Paintings of All Time, by Risto_Saarelma. Based on lukeprog's listology, itself based on Piero Scaruffi's 1000 Greatest Western Paintings of All Times.
• Ear Training (chords), by Pablo_Stafforini. Contains sound samples of about 40 of the most common chords, in root position.

Communication

• Adele Faber & Elaine Mazlish's How to Talk So Kids Will Listen and Listen So Kids Will Talk, by divia.
• Kerry Patterson, Joseph Grenny, Ron McMillan & Al Switzle's Crucial Conversations, by divia.
• Marshall Rosenberg's Nonviolent Communication, by divia.

Dreaming and Psychedelia

• MAPS's Responding to Difficult Psychedelic Experiences, by divia.
• Stephen LaBerge & Howard Rheingold's Exploring the World of Lucid Dreaming, by divia.

Medicine

• 10 Rules for Dealing with the Police, by divia.

Mnemonics

• How to Formulate Knowledge, by alexvermeer. Based on Piotr Wozniak's 20 Rules of Formulating Knowledge. [See also divia's similar deck]
• The Major Mnemonic Memory System, by alexvermeer. Contains cards for the sounds associated with 0 through 9 as well as 100 pegs.

Psychology, Psychiatry and Neuroscience

• Advanced psychological statistics, by Emily. "mainly about various kinds of modelling approaches and meta-analysis."
• Functional neuroanatomy and neuroscience methods, by Emily. "basic stuff about various imaging techniques, a little bit of psychopharmacology."
• General psychology, by Andy_McKenzie.  "Includes cognitive biases (about half of the list I posted here; I'm still planning to make the rest), some personality psyc, and also a few taken and modified from Divia and Alex."
• List of Personality Disorders, by Pablo_Stafforini. From Theodore Millon's Personality Disorders in Modern Life.
• Peter Gray's Psychology (6th ed.) (in progress), by Pablo_Stafforini.
• Quantitative and qualitative research methods, by Emily. "fairly basic research methods stuff."

Rationality and Cognitive Science

• Cognitive Science in One Lesson, by jsalvatier. lueprog's summary of José Luis Bermúdez's Cognitive Science.
• List of Cognitive Biases and Fallacies, by phob. Based on Wikipedia's List of cognitive biases and List of fallacies.
• Rationality Habits Checklist, by Qiaochu_Yuan. Based on this post.

Self-Help

• Carol Dweck's Mindset: The New Psychology of Success, by alexvermeer.
• David Burns's The Feeling Good Handbook, by Pablo_Stafforini.
• Get Motivated, by alexvermeer. An experimental deck for getting yourself motivated using the advice from Piers Steel's The Procrastination Equation and the author's own How to Get Motivated poster.
• Richard Wiseman's 59 Seconds, by Dorikka.
• Tim Ferriss's The Four Hour Work Week, by alexvermeer.