I use ankle weights, 2lbs. each. It is surprising how much I feel that little amount of weight.
There are several exercises I do with the ankle weights - leg lifts by bringing up your knee as high as you can, side leg lifts, back leg lifts, running in place, standing and then bending as if you’re going to sit and just touch the seat of a chair and come back up. Start with doing 8 reps of each and increase to 2 reps and 3 reps. Sometimes I’ll just walked around my house as I do chores with the weights in until I start to feel my legs say “enough.”