There are many types of knits. Lets discuss them:

Warp knits: Warp knit fabric is constructed with many yarns that form loops simultaneously in the lengthwise direction. Each yarn is controlled by its own needle and interlocked with neighbouring yarns in zigzag fashion.  This interlocking produces fabrics that are usually runproof and have limited stretchchability in varieties ranging ranging from sheer laces to fake furs. Warp knits can be produced only by machine because of their complex structures. Tricot and Raschel are the most widely produced type.

Tricot knits: Fine ribs on the face, flat herringbone courses. Technical differences are not visible to the eye but they do affect performance. Double and triple warp tricots are runproof- single warp is not. Tricot knit usually made from fine yarns, cottons or synthetic. They have a soft, draping quality and are suitable for linings, loungewear, lingrie and dresses.

Raschel knits: A wide range of fabrics from fine nets to piles. The most typical raschel pattern has an open lacy structure with alternating thick and thin yarns. Any yarn type is suitable including  metallic and glass. Warp knits are widely available and comparatively low in cost- the machines used can produce upto 40 sq ft of fabrics per minutes.

Weft knits: Weft knits fabric is constructed with just one yarn that forms continuous rows of loops in the horizontal direction. Basically the machine stitches are exactly like those done by hand and fabric characterstics are similar i.e the stretch is greater in width then in length and a broken loop releases others in a vertical row, causing a run. Different knit categories- single and double.  Single knits have a moderate to a great amount of stretch. Though very comfortable to wear, they may eventually sag in stress areas. Also their edges tend to curl, creating difficulties in cutting and stitching. Duble knits have body and stability similar to those of a weave.

Plain jersey knits: Plain jersey knit is a single construction. The face is smooth and it excibits lengthwise vertical rows. Plain knits stretch more in width than in length

Purl knits: A single construction in which loops are pulled in alternative rows to the front and back of the knit causing a purl stitch to appear on both sides of the fabrics.

Rib knits: A single construction with rows of plain and purl knit arranged so that the face and the reverse sides are identical. Rib knits have expensive stretch and steady recovery in the crosswise direction which makes them especially suitable for cuffs and waistbands.

Patterned knits: Complex variations on the basic plain and purl knits. A cable knit is a typical example of a pattern knit.

Double knits: Double knits produced by 2 yarn and needle sets working simultaneously. Double knits have firm body and limited stretch capacity depending on design, the face back may look same or different. Some complex double knits resemble the woven dobby and jacquard patterns.