The Orcs Hand seems to be too small, and the lower Arm could be more muscular.

Nice works.

You have the best chances of selling your models, if you either:

#1 do specific and exclusive contract work for a game project/company

or

#2 Do a set of figures, wich have the same style.
Somthing like basic 2 Male and 2 basic Female Models. And several attachable
Amor / Clothes models, that fit the amiations. The skins of the models can be
then editied for even more variety.
+ Several Models of evil humaniod characters (like your orc), and some animals
(like a wulf, a Dragon etc)

You can sell them in a "fantasy Characters" pack then.
The purchaser can do further edits on the skins then for customization.

Single models are not much help for a game, If every model in the end has a different
style / artist that did them. This would look inconsistent then.

YOu style looks good, so you should make a versatile collection for fantasy games then.