Here are a couple:
Facing the barre with two hands and standing in first position, make slow tendus to the side, working carefully and methodically through the foot.
Slow élevés facing the barre in first position (working particularly to come down with control).
Temps liés facing the barre, exaggerating the work through the foot (really pressing down) and then repeating using plié as you make the step.
Making sur-le-cou-de-pied from 5th. Both side and back as well. Help make the foot more facile and shapely with better control.
With feet parallel, roll up and down -- slowely and with control.
Hope these help!