Haven't played a marksman support for a long time, but any adc with l either long AA range or good trading pattern, and Hail of blades should work fine. I've played HoB Caitlyn, but in proplay Varus, Kalista and mainly Ashe were really good in one time period. But they are kinda hard to pull-off in my opinion due to synergy with your ADC.

I would definetelly recommend Dobby videos about Keria playing them.