bristol

My favourite is missing from the list: \usepackage{needspace}.

LaTeX' page-breaking algorithm gets it right most of the time but sometimes a bit of help makes it even better, i.e. a

    \needspace{4\baselineskip}
    \subsection{Something}
    Lorem ipsum ...

tells TeX to insert a pagebreak here if there's fewer than 4 lines of text left on the page, otherwise just carry on. Unlike \pagebreak[n], this is not optional.

\usepackage{refcheck} belongs in everyone's toolbox as well.