The following filters are for a template report. They should help you see which templates are being used, or not. How often, or not. And when.
Associated CUR PLN ONH projects (projects made from these templates are in progress)
EXISTS:a:$$EXISTSMOD=EXISTS
EXISTS:a:$$OBJCODE=PROJ
EXISTS:a:statusEquatesWith=CUR PLN ONH
EXISTS:a:statusEquatesWith_Mod=in
EXISTS:a:templateID=FIELD:ID
isActive=true
isActive_Mod=eq
Associated Projects in Past year (these templates got used this year)
EXISTS:a:$$EXISTSMOD=EXISTS
EXISTS:a:$$OBJCODE=PROJ
EXISTS:a:entryDate=$$NOW-1y
EXISTS:a:entryDate_Mod=gte
EXISTS:a:templateID=FIELD:ID
isActive=true
isActive_Mod=eq
Associated Projects (these templates got used at some point)
EXISTS:a:$$EXISTSMOD=EXISTS
EXISTS:a:$$OBJCODE=PROJ
EXISTS:a:templateID=FIELD:ID
isActive=true
isActive_Mod=eq
No Associated CUR PLN ONH projects (no projects made from this template are currently open)
EXISTS:a:$$EXISTSMOD=NOTEXISTS
EXISTS:a:$$OBJCODE=PROJ
EXISTS:a:statusEquatesWith=CUR PLN ONH
EXISTS:a:statusEquatesWith_Mod=in
EXISTS:a:templateID=FIELD:ID
isActive=true
isActive_Mod=eq
No Associated Projects in Past year (this template hasn't been used in a year)
EXISTS:a:$$EXISTSMOD=NOTEXISTS
EXISTS:a:$$OBJCODE=PROJ
EXISTS:a:entryDate=$$NOW-1y
EXISTS:a:entryDate_Mod=gte
EXISTS:a:templateID=FIELD:ID
isActive=true
isActive_Mod=eq
No Associated Projects (this template has never been used)
EXISTS:a:$$EXISTSMOD=NOTEXISTS
EXISTS:a:$$OBJCODE=PROJ
EXISTS:a:templateID=FIELD:ID
isActive=true
isActive_Mod=eq