These parts are as big as a minifig's upper torso. For a 6 inch scaled hero it's just a small bag which can be placed on belts, legs, pants and armor. Some of them are even functional :)

Most of Minifig-weapons can be used by 3 3/4 scaled figures.
When it comes to money ... well, the bills can be used by 6 inch scaled figures, the coins by 7 inch +

There are plenty accessoires for minifigs, some are smaller, some are bigger. Just try out, watch reviews, and let creativity be your guide.

Lego also offers you a lot of technically usefull parts.
Ball and socket system allows you to extend the range of flexibility, where ever you use it. Gears and levers add some more machine-look to your figure or display.
Flexible pipes are very usefull for cyborg/robot/futuristic figures. The thicker ones are hollow.
My personal favorite: chains. I mean you can use real chains, but I prefer everything to be made of plastic (when it's about action figures), because any "real" material does not fit to the style of an action figure as a replica. To be a replica completely made of plastic is for me the meaning of an action figure. Real materials suit 12 inch/ doll customs much more.

Yeah, they're really flexible :D

The main reason why I write this tutorial are the translucent parts. Crystals, laser, fire, ice, eletricity - after you're done with your figure, you want to make some dynamic pictures with powers of the heroes, but you lack the effects. Of course there are trademarks like Tamashii Nations who would offer you some effects, but those are mostly basics. When it comes to specific powers you're on your own. Or with Lego :D
Additionally there are metallic coloured parts. But the most importan fact about all that is, that 90% of Lego-parts are made of coloured plastic, not painted one.

I bought these for my Skyrim display - potions.
Of course there are other shapes and colours :)

Whatever you like it to be. I think it would make a great laser/energy shot, or some decoration for a machine-like hero.

Well, that's not the most realistic effect: the pieces are flat, so you'll need to combine them and use some hot glue ... I just stucked them into the piece of styrofoam.

I secured this piece with a rubber band (because the custom I bought it for is not finished), but to me it already looks promising :)

A bright blue one could be good for an Ironman.
Different sizes, shapes and colours - with print or clear. It's your choice.

Unfortunatly I had no coloured Zamor-Spheres left ... but let's imagine he does the Kamehame Ha thing ... or tries out shot put.
These spheres can be used as decoration or magic-/energy-effects.

Bionicles and Lego Technic will provide you with those parts you normally search in your fodder - weapons, armor, body parts, gear. The only problem you might have is, that most Bionicle figures are up to 8 inches tall which results in some parts being to big for what you planned.

His "upper leg armor" was a shoulderpad of a knight. That's waht I ment when I wrote too big.

Bionicles had various weapons - swords, claws, blasters, axes, hammers, spears ... some more techno-styled, some less, but most of them a bit too big.
Anymways, many online game and anime characters use weapons an average human should not be able to lift ;)

Quite big, but i think it would look good.

Flexible spikes and tentacles, wings, fins, teeth, horns ...
in combination with ball-and-socket joints you'll be able to create wings with a decent range of motion!

Some parts just look tough enough to be part of a custom or a display.