The Genius Guide to Simple Monster Templates for Pathfinder RPG

Not particularly creative, but fine for simple templates. One template (eternal = an immortal creature) feels not like a proper template, because it doesn't really change anything, it's just immortal, period. But still serves as an inspiration. The templates are probably more useful than a lot of more complex templates, because they are easier to use, and thus more likely to be used and especially reused.