Greetings
I would like to know if anybody knows a good site or an app to make sketches of characters. It should be like Heromachine, but more modern.
Played around with makehuman too, but I want to be able to do something on my tablet and phone.

Just try out different painting apps on your phone.

For Pathfinder and StoreyMinus, I actually used real world images for my characters. Also, I believe there are (as said above) apps you can get to generate faces (but I find that real world images are more immersive).