Of course you always have your basics –
squats- regular, 1 legged squats or wall squats
wall squats holding for a minute at a time, can even switch up the wall squats by swapping legs and holding them straight out in front of you during the wall squat so squat with back against wall, then lift right leg (still in squat position) hold then place right leg in squat position with left. Then take left leg and lift straight out in front and hold, put back in squat position and switch to the right leg lift.
stairs, stair climber, or a step up
AND OF COURSE BARRE!!! I LOVE BARRE WORKOUTS FOR LEGS ESPECIALLY!!! THEY REALLY TONE AND LENGTHEN!!
thanks to theberry for the images!