The traditional triangular section needle with softened edges to ensure that no damage is caused to the fabric being stitched. The numbers are based on wire gauge see here for a note on that so the larger the number, the smaller the needle. You can order them individually or in assorted packs.
Curved needles most widely used nowadays for upholstery, but also needle hitching.
Loaded with twine, these are used as a sort of manual shuttle when making nets. Also very handy for attaching netting to things like railings.
The Speedy Stitcher is effectively a manual sewing machine, which forms a lock stitch as it goes. It is suitable for a variety of materials, including canvas, leather, sailcloth and webbing, and comes complete with two needles and a bobbin of waxed thread. The results obtained - in my case at any rate - are a triumph of technology over talent (or lack of it). Learn to stitch here