I love using single leg movements... for myself and my clients. Unfortunately for new people or untrained people, single leg movements can be tough. They lack overall strength, therefore even doing a squat can be challenging. Then a single leg movement gets thrown at them and they struggle. Not only is it physically challenging for them, but mentally they feel defeated and possibly even embarrassed because they are unable to perform it well.
I love RDL's, so you can imagine I enjoy prescribing single leg RDL's. Instead of worrying about them balancing, or counterbalancing the other leg or falling over, I use the kickstand RDL as the first progression. Works like a charm.
In this exercise, prop one foot slightly behind the other, toe on the ground, knee slightly bent. From there, you can perform the single leg RDL with the planted leg, while the "kickstand" leg is helping to balance.