I sell a lot of fingerless fleece and wool gloves, as wademaster mentioned. Also sell a good many pair of "flip mitts" either by Simms or Chota. The mitt feature offer more warmth but tends to be a little bulky and can snag on stuff. The Chota neoprene gloves have been really nice for driving the boat and handling stuff around the water....but don't offer exposed finger tips for dexterity and knot tying. When your pull the neoprene glove off, your moist hands chill pretty quick. On a bad day, I like to keep a couple of the handwarmer packets in my jacket pockets so I can slip hands in there for a quick warm up. The packets will heat pretty well for quite a few hours. You can also buy larger heat backs called body warmers...
Several years ago, there were some fleece pouches on the market which would attach around your wrist. You could then put a handwarmer packet in each pouch on the inside of each wrist. They worked great. Although they did add some warmth, the main concept was to "trick" your body into maintaining an increased blood flow to the hands. As roostertail mentioned, the body diverts warm blood from hands and feet to keep core organs and brain warm. The heat packets on the inside of the wrists helped maintain increased blood to the hands. I found them to be really nice, as did several guides, and golfers. I don't think the fleece pouches are available any more....but I have seen some gloves and mitts with a pouch on the inside of the wrist for heat packs. There are probably several options that could be contrived to hold a heat pack there...without letting bare skin come in contact with the heat pack and run the risk of a burn. Some tight fitting jacket cuffs interfere with heat packs on the wrist.