Similar templates at English sister projects [edit]
mta Meta-wiki Tl/doc
wpd Wikipedia Tl/doc
cms Commons Tl/doc
wbk Wikibooks Tl/doc
wsp Wikispecies Tl/doc
wvy Wikiversity Tl/doc

{{Tl}} and {{Tl2}}

are simple macro templates used to display a template name as a link. Tl stands for Template link. 
Tl2 differs in that it displays an arguably clearer result like {{Tlx}}, and also like takes the named parameters 'SISTER=xx' and 'LANG=ll', so that it may also be used to list and link to templates on other English and non-English language sister projects.
related
{{Tlx}} displays with the same enhanced presentation, and also expands several 'placeholder' parameters to generate a sample template call.

 {{Tl|template name to display}}
and
 {{Tl2|template name to display}} -- local link, just like Tl.
 or
 {{Tl2|SISTER=V:|template name to display}} -- displays a template on Wikiversity
 or
 {{Tl2|LANG=fr.|SISTER=wikisource|template name to display}} -- displays a template 
                       on the French Wikisource sister project.
Code Result
{{Tl|x0}} {{x0}}
{{Tl2|x1}} {{x1}}
{{Tl2|SISTER=M:|3x}} {{3x}}
{{Tl2|SISTER=wikibooks|LANG=de:|WP}} {{WP}}