Currently, I have Pumpkin Duke, Valentine, Cupid, Vlad, Ghoulem, Medusa, Li Nick, Skull Knight, Anubis, Revenant, Dracax, Beast Tammer, Candy Kane, Harpy Queen, Santa Boom. Town hall level 19.
Can anyone help me to choose the best heroes to farm HBM ?
I assume by "farm" you mean "clear for the first time". Once you beat an HBM level once, you can start sweeping it, which guarantees a 100% success rate. We no longer need to farm HBM anymore.
Also, it would help to mention which HBM level you are on, and at least the general strength of your heroes.
That said though:
PD, Valentina, Vlad, Ghoulem, Anubis, Santa
Those 6 will work all the way to HBM T.