If you've never heard of the Kang squat before, it's a terrific tool to improve squat depth, eccentrically overload the hamstrings, and improve squatting mechanics and mobility.
To get the same benefits with a single-leg emphasis, it makes sense to do a rear-leg elevated Kang squat – a variation I hadn't seen before I tried it myself. Starting with a deep hip flexion before dropping to a bottom position takes eccentric control, and it really torches the glute on the leading leg.
Rear-Leg Elevated Kang Squat
Don't forget, though, the trailing leg is mounted on a bench, so you're still going to get all the quad training and hip mobility benefits on the other side. The rear-leg elevated Kang squat just adds an invaluable element of posterior chain work.
This one doesn't take much weight to feel, and fewer reps are the smarter call. I like 6-8 slow-tempo reps per leg.