As recommended by this answer, I have opened a meta question for proposed entries for the glossary. As each suggestion is added to the glossary, please strike it out in the answer here.
Maybe this is opening up a big can of worms, but I think the glossary should include (all!) the roshei tevos in ~frequent use in a beis midrash. If certain abbreviations haven't been used on this site yet, it is only a matter of time, I think, until they are.