To this day you can buy passive cables which separate out S-Video and composite signals from VGA. There's always a warning to check whether your graphics adapter output these over the VGA connector. While I have seen a number of video cards which had a separate S-Video connector, up to the ATI HD 3650 and the Geforce 6200 but I have never in my life seen or heard of a card which outputted S-Video over VGA. Anyone...?
Some Matrox cards output composite and S-Video using the HD15 port; for example, the G450 PCI. The adapter cable was optional though and isn’t commonly included with the graphics adapter.