The worksheets on this site work great for reinforcing note recognition and some basic sightreading. Each of the following categories contain three separate worksheets that can be downloaded for free:

Bass Clef: C Position
Bass Clef: Line Notes
Bass Clef: Space Notes
Bass Clef: Line and Space Notes
Treble Clef: C Position
Treble Clef: Line Notes
Treble Clef: Space Notes
Treble Clef: Line and Space Notes

Here’s a demo image of one of the Bass Clef: Line and Space Notes worksheets: