Combinations of knitting stitches produce a huge array of different designs. Even if you just use the basic knit and purl stitches, the possibilities are endless.
Some stitch patterns are reversible (like garter stitch) which means that the front and back of the knitted fabric look the same. This means there is no right side or wrong side (which occurs in stockinette, for example).
Simple Knitting Stitches
Here are some simple stitch patterns to get you started
Garter Stitch

Cast on the required number of stitches (or any number you fancy if you are just learning)
1st Row: Knit to end
Knit every row until the required size is obtained
NB This stitch pattern is reversible
Stockinette Stitch

Cast on the required number of stitches (or any number you fancy if you are just learning)
1st Row: Knit to end
2nd Row: Purl to end
Repeat these two rows until the required size is obtained
Double Rib Stitch

For a “two and two” rib, cast on a number of stitches divisible by four
1st Row: *K2,P2, repeat from * to end of the row
Repeat this row for the length required
Seed (Moss) Stitch

Cast on an uneven number of stitches
1st Row: *K1,P1, repeat from * to end of the row, ending in K1
Repeat this row for the length required
NB This stitch pattern is reversible
Basket Weave Stitch

Cast on a number of stitches divisible by 10 and 3 extra stitches
1st Row: *K3,P7, repeat from * to the last 3 stitches, knit these
2nd Row: *P3,K7, repeat from * to the last 3 stitches, purl these
3rd Row: Like the first Row
4th Row: Purl to end
5th Row: P5,*K3,P7, repeat from * to the last 5 stitches, purl these
6th Row: K5,*P3,K7, repeat from * to the last 5 stitches, knit these
7th Row: Like the fifth row
8th Row: Purl
Repeat these eight rows for the length required.
There are many more patterns you can make with knitting stitches, but these ones are good for beginners.
Have fun!