That's a bit of an open ended question Kahi. First off, what size or scale are we talking here?
Pretty much all of my MOCs have articulated fingeres/hands these days. Only my earlier stuff doesn't. As Hawkflight mentioned most people use the exo force/bionicle Minifig arms as fingers. That's the widest range of part used for fingers.
The T bar configuarion is what seems to be "standard" but honestly its crap. I think I've used that hand design once and I don't find it very useful. The hand design I use I first saw from Lord Gringat on MOCpages/DA. I use it on a lot of my MOCs but it can be seen here on Matteo
The way it works is you stick a claw piece into the axle hole of an old style socket a 1X2 plate into the square notches in the socket(it provides a light grip) then you stick a modified plate with the bars(look at the photo for the specific one) and attach it to both the plate and the clip part of the claw. This provides a nice sturdy connection to the socket element. Then you can attach two fingers to that, and like with the hydraxon hand use a tap piece and can attach a thumb, or two more claw parts connected together provides the same solution albeit a little less compact.
Another alternative that is relatively new thanks to the mixel ball joints is to use those. I've created a sort of test variant of the smaller hand design. .
I haven't actually created a hand design with mini balljoint digits, but I don't think that would be an efficient method as the fingers would be quite long, making the hand rather large. I could see it being useful for a characterized hand, but not for something proportionate to a "standard" sized build. This hand design though was made with the mindset that it could be customized to better fit the proportions of a figure.
If you want something a little more articulated and bigger, the next option is technic style click joints as seen here
This is probably my favorite hand design to use the click joints. its very articulated. It uses a combination of the click joints and the bar and clip system to create a very articulated hand.
Finally, the last jump in size is to use balljoints. Now we're talking axon style hands. Interestingly enough, you can still rely on the bar and clip system to provide excellent articulation to the hands as I've done here with Saxum, provided the fingers aren't too heavy, otherwise they'll overload the bar and clip aspect of this design.
He uses the big Hero factory Paw piece, the small claw piece from the other hand designs and sockets attached to those via their axle holes, then the Hordika necks in the sockets to create the actual digit. This design is great for bigger MOCs or MOCs where you want them to have really large hands. And because it uses the Hero Factory Paw piece, it connects to any arm design that ends in a balljoint, which most arm designs do.
I know this is a bit of a read but I hope it helps you guys with your MOCs and inspires you to come up with your own designs. If you do copy one of mine(except for the one I borrowed from Gringat) I'd appreciate you giving credit. Thanks.