documentclass{article}
usepackage{fontspec}
usepackage[style=authoryear]{biblatex}
begin{filecontents}{jobname.bib}
@ARTICLE{test1,
    AUTHOR = {John Smith},
    TITLE = {A Tremendously Interesting Opinion},
    SHORTTITLE = {TIP},
    JOURNALTITLE = {Journal of Tremendously Interesting Opinions},
    SHORTJOURNAL = {JTIO},
    VOLUME = {1},
    NUMBER = {1},
    YEAR = {1950},
    KEYWORDS = {important},
}
@ARTICLE{test2,
    AUTHOR = {John Tumble},
    TITLE = {A Tremendously Interesting Idea},
    SHORTTITLE = {ABITLONGERSHORTTITLE},
    JOURNALTITLE = {Journal of Tremendously Interesting Ideas},
    VOLUME = {1},
    NUMBER = {1},
    YEAR = {1960},
}
@BOOK{book1,
    AUTHOR = {Peter Johnson},
    TITLE = {A Tremendously Interesting Title of Book One},
    SHORTTITLE = {ATIT},
    TRANSLATOR = {John Smith},
    ORIGLANGUAGE = {german},
    VOLUME = {1},
    LOCATION = {London},
    PUBLISHER = {Publisher},
    YEAR = {1950},
    KEYWORDS = {important},
}
end{filecontents}

addbibresource{jobname.bib}

begin{document}
nocite{*}

%printbiblist[title={Abbreviations}]{shorttitle}
printbiblist[title={Abbreviations of Important Publications},keyword=important]{shorttitle}
printbibliography
end{document}