Other than ChinaSMACK, do any other glossaries of acronyms used in Chinese, like PK, ZF, GCD, TMD, JC, etc exist?
As someone involved in chinaSMACK, I wouldn't say the glossary is "outdated" since the terms on there were notable enough in our translations of trending Chinese internet content that we decided they should be added. 

It is, however, far from comprehensive, precisely because we only tend to add to it as a consequence of the terms we see often while translating. We don't go out of our way to add to it, since it is meant to serve as a reference to supplement our translated content. For example, if a Chinese netizen comment includes the acronym LZ, we can just leave it as "LZ" in our translation and instead link that "LZ" to its entry in the glossary. We feel this allows to keep some of the form and flavor of the original in our translations, rather than just translating it directly to "original poster" (which is what LZ simply means). 

I suppose we don't delete stuff that is no longer as commonly seen ("My dad is Li Gang") and thus they might seem "outdated" but because we have content that links to those entries, we leave them in and figure they are still notable for having been popular at a point in time.

If you want another resource that is also in English, check out the Grass Mud Horse Lexicon by China Digital Times: 

http://chinadigitaltimes.net/space/Grass-Mud_Horse_Lexicon
http://chinadigitaltimes.net/space/Introduction_to_the_Grass-Mud_Horse_Lexicon

Note: CDT is blocked by the GFW in mainland China.

CDT built this quite awhile after chinaSMACK had its Glossary. It used to use Wiki software (doesn't seem to anymore) and, to be honest, I remember it feeling more comprehensive than it looks now that I'm revisiting it. I can't post more than two links so look for the search by alphabetical order page as well.

If you look through their categorical organization and list of terms, you'll notice a strong emphasis on cataloging terms involving stuff that appears more in circles discussing politics, censorship, and dissidence. This is because of CDT's editorial focus, whereas chinaSMACK tends to focus more on mainstream Chinese internet culture. For example, there doesn't seem to be an entry for 熊孩子 (naughty/unruly kids) though it is currently a common internet slang term both in terms of humor as well as referencing certain social issues involving children.

Hope this helps!

P.S. Sorry if it doesn't help if you're looking specifically for acronyms. Acronyms are often just of the Chinese word in pinyin, and weren't created or used specifically to be acronyms or shorthand but to avoid censorship of certain characters/terms. For example, the use of GCD (共产党) is different in nature than YOLO (You Only Live Once). The latter could be said to be a way of shortening a catchphrase, but the former was designed to avoid filters or searches for the actual Chinese characters.