Professional designs

There is no need bothering about whether 150 or 1000 templates, because actually there are more then enough for average daily use. Also, I may not call these templates, but a collection of elements and shapes professionally designed and arranged in slides. You may just copy any slide you like to your work and add your content. I would suggest that pre-add some animations to the shapes to make the "templates" more ready-to-use.

getReadyTeddy about 1000 Slides - Templates for PowerPoint and Keynote