Below are some spreadsheets that might be of use. Let me know of any errors.
(Yet another) simple slope calculator and graphing tool. Calculate the slopes for conditional values of a moderator in, well, moderation analyses. I was in trouble like halfway into this sentence. Better examples exist, but I like the formatting on this one. Link.
GAPIM conditional values and graphing tool. Calculate conditional values and a graph for output from the GAPIM model (Garcia & Kenny, 2012). Link.
ICC(1) and ICC(2) calculator. Intraclass correlation coefficients. Be cautious with small group sizes when calculating these. Link.
Bayes theorem calculator. Relevant, relevant, and VERY relevant. Link.
Post-hoc ad-hoc average power calculator. Very mixed feelings about this one--way too many assumptions, and this is not how power should be calculated. Occasionally, however, you might need to do a quick calculation of average power on a finalized model (read: paper is under review, and you are reviewer #2). It's VERY back of the envelope and should not be read to generalize for the population. However, it could be useful if you somehow had good standard error estimates (say, from a tool like PiNT, if you're old-school), and wanted to save a few calculations. Again: extra careful with this one. With that being said, Link.
From inter-item correlations to alpha and back again. Useful? Who knows. I needed it once. Link.
Dichotomization and correlation attenuation. Calculates how much a correlation diminishes (everything else being equal) when a continuous variable is made dichotomous, with a cut at given SDs away from the mean. See Cohen, 1983; also includes a note for a reverse procedure that can be used to "correct" results attained via dichotomous variables, and such should be used with a ton of caution (I'm sensing a pattern with these spreadsheets). Link