When I need to do that I define two abbreviations and use them one after another. Thus, alt-b produces <ref>{{cite book and alt-B produces | isbn= }}</ref>. So alt-bB produces <ref>{{cite book| isbn= }}</ref>. It's easy and takes very little effort to type.
If I want something longer, with carriage returns etc. I can combine the functions of Ukelele with those of TextExpander. For example, if I type alt-J then Ukelele gives jpolicy, which TextExpander, as soon as a space or punctuation is added, expands to
The aim of the Journal of Theoretical Biology is to
publish theoretical papers which give insight into
biological processes. The biological significance should
be clearly stated. Highly speculative papers not
based on current biological knowledge will not
be acceptable.
It is essential that papers be accessible to as wide a
readership as possible. Every effort should be made to
make the main points of the paper intelligible to biologists
as a whole. Authors should thus make it clear how any
mathematical models relate to the biological problems
they address.
I don't have occasion to use this any more, but at one time I used it often for reporting on papers whose authors didn't appear to have read the Instructions to Authors.