I frankly have no idea anymore and I need some help trying to cipher out what is no longer in cannon and what is now out of date.
So far there is
Contessa Valentina Allegro de la Fontaine (In Secret Warriors she was shown wearing the Madame Hydra Robes)
Viper currently shown as Madame Hydra but then what happened to Contessa
Queen Hydra is currently making moves in Captain America as the de facto Hydra orginization but the thing is that even she acknowledges a Madame Hydra (which brings me back to my main point of who the hell is the leader of Hydra?)
Baron Von Strucker who I swore was the leader of Hydra in the beginning of Secret Warriors.
Also in Avengers 20 I also saw that apparently Hydra and A.I.M are now working together or one in the same (atleast that's what I read idk I may have read that wrong) but in Daredevil 6 A.I.M and Hydra where pointing guns at each other over the disk thing.