There were 10 receptacles/9 plugs[1] before USB-C. Of those 19 total, the only ones I've never seen in the wild are the USB Mini-A receptacle and the USB Micro-AB receptacle.

Receptacles: USB A, USB 3.0 A SS, USB B, USB 3.0 B SS, USB Mini-A, USB Mini-AB, USB Mini-B, USB Micro-AB, USB Micro-B, USB 3.0 Micro-B SS

Plugs: USB A, USB 3.0 A SS, USB B, USB 3.0 B SS, USB Mini-A, USB Mini-B, USB Micro-A, USB Micro-B, USB 3.0 Micro-B

[1] https://en.wikipedia.org/wiki/USB_hardware#Host_and_device_i...