According to EndocrineWeb, the main hormones produced in the ovaries include progesterone and three estrogens: estradiol, estriol and estrone. Other hormones produced by the ovaries are relaxin, inhibin and, according to Wikipedia, testosterone.
As EndocrineWeb notes, estrogens and progesterone are vital for the development of secondary female sex characteristics, including the development of reproductive organs, and preparing the female body for pregnancy. Progesterone is also the main hormone for maintaining pregnancy as it prevents uterine contractions and prepares lactation glands. EndocrineWeb and Wikipedia also explain the importance of inhibin and relaxin in maintaining pregnancy. Inhibin regulates ovulation through inhibition of follicle-stimulating hormone secretion, while relaxin offsets hemodynamic changes during pregnancy and relaxes pelvic ligaments before birth.