.. single leg deadlifts with a kettlebell.
maybe better for core stability than usual deadlift. The core strength is not just from lower back and abs, there is the side muscles, plus ability to handle some torsion and the reflexes to do so. I imagine single leg DL would do the side, involve some balance (fire up the reflexes) as well as the other things the regular DL does.
My routine is two sets of the following:
dumbbell reverse flies - really light weight done slow (for posterior shoulder stability).
dumbbell overhead presses,
dumbbell bicep curls,
straight leg, bent over dumbbell tricep extension. Done without using the free arm supported on anything. That way it puts a little load on the lower back and some torsional load too because I do a set for one arm at a time.
Pull ups. 5 or 6 max.
push ups with hand on an exercise ball. Some times with only one leg on floor - to introduce wobble and torsion.
some slow straight leg jack knife thing with hands on the exercise ball.
both legs on exercise ball with one hand on the floor plank thing - has wobble for the reflexes and torsion. Hold that 30 seconds, then do the other arm.
Set of about 6 normal speed surfboard popups on the floor.
This is what I do just once a week, I'm not recommending it or anything like that because I am not qualified to do so and everyone is different. Its just what I do, some of it prescribed to me. I have picked it up from more than one health professional and also just made some stuff up too. Nothing direct for the legs, but I'm skateboarding and on a good day of surfing my legs get worked a bit then.