A template that complements ((smallsup)), i.e. it subscripts <small>-sized text:
((smallsub|Text to be subscripted)) produces: Text to be subscripted
This template may be listed at Wikipedia:Subst as a good candidate for substituting (i.e. ((subst:smallsub)) ). On a page that uses the template many times, however, this is likely to clutter and lengthen the page significantly.