I had to do a ton of variations :(. The sad face is because I really love gym equipment so much. But I am happy to present some great alternatives to those of us at home!! Here we go!
Seated Leg Curl: Swiss ball bridge. Lying on your back, put your heals on the swiss ball. Then keeping your feet in place, roll the ball towards you, lifting your pelvis towards the ceiling. The key is to get your butt all the way up so that from knee to shoulder your body is flat.
Leg Extensions: I did fast body weight squats or jump squats for these. Shoulder-width stance.
Abductor Machine: I have a sports resistance band designed for the legs – it is a really tough tubing band with straps on each end to velcro around your ankles. I strapped them to my ankles and, seated, I did the abductor motion (fully flexed = open; starting position = closed knees).
Lying Leg Curls: I did the same exercise as the Seated Leg Curl above. This worked perfectly since it was supersetted with Adductors (see below)
Adductor Machine: Lying on back, put swissball between knees and SQUEEZE.
Leg Press: Wide stance barbell squats. Drop set to failure.
Seated and Standing Calf Raises: Hold weights on knees for seated and on shoulders for standing.