www.pixelguns.com
I've posted before for RMVX, but I'm currently in the process of resizing them and making the site a little bit easier to navigate. I can make a few Weapon Files if people need help, but for now it's pretty easy to make your own (Thinking of making a tutorial on setting it up) and just paste them in.
I prefer larger sprites so the guns are reflective of that, but will definitely be updating the guns to get them smaller. For now, all of the pistols are good size.
Here are some examples of my work.
(Pistols)
(SMGs)
(Rifles)
(For ambitious people)
(I even do requests. Lancer GoW / Mass Effect Avenger)
(WWII)
(Accessory Items)
(Attachments)
All Commercial Free
If you have requests, please fill out the form on my website because it'll send it to my email.
Good luck!