Yep. And so does the polarity and the amperage as well. Most devices have the centre pin as the positive but if you connect a positive centre pin power supply to a negative pin on the device then you will most likely get a fizzle then a bang. Don't assume that an additional couple of volts either way doesn't matter either. It most likely will.

Most rechargeable devices have the Voltage and polarity marked beside the connector. The power supply will have the output voltage and amperage and polarity marked (the centre circle will indicate either a + or - symbol) as well.

The solution is to get a set of carboard boxes and give each box a voltage such as 3V, 5V or 12V etc and the centre pin polarity i.e. + in red marker pen and - in black marker pen, then go though each power supply one by one. Once separated out it should be a lot easier to determine which power supply matches up with the correct device by the size of the pin connector and the amperage rating.