Try them, and if you don't like them make your own. The 'set' command is a great way to construct plots of specific functions. Click the middle button to read the coordinate under the cursor. To print the cursor positions sequentially on the screen try typing 1 through 9, moving the cursor between each number. Right or left buttons exit.
Type sketch a b, where a and b are letters.
Click the middle button to mark a point, and click left or right to end. This marks points on the graph. Fits a cubic spline through the points made by sketch. Points must increase monotonically in x. Expand an area using the cursor.