I like this as it is an interactive unit circle that students can move the arrow around to create the required triangle.

Students have a choice of degrees, radians or pi so they can find the same values for each choice of systems. Theta is listed on the lower left side. In addition, the values for all 6 trig ratios are listed across the bottom. There is a button in the upper left corner that allows students to bring up the table listing values for the main 6 trig ratios.

I've had my students use this app when they've filled out their own. The nice thing about this app is students can look up the values for any theta. Furthermore, I have let them use this app to find values for trig ratios on their worksheets. If I wanted to take things a step further I could have them draw the angles for the problems.