Many teachers are not entirely comfortable writing report card comments. I have spent hours and hours over the years developing and refining my report card comments. It is necessary to reflect student progress and give feedback to parents, and both groups always appreciate thoughtful comments that indicate you know the children well.
This is a set of trimester ending comments for a sixth grade science class of 19 varied students, including gifted, ESL, all ability levels, and even special needs. The topic for the trimester was human body systems. You probably know that many of these comments can be tweaked and applied to your students as you write your own comments. Why re-invent the wheel?