You can view a list of supported devices in MPE+ itself, or online. If a device is not listed in MPE+ it typically means that MPE+ cannot extract any data from that device. The possible exceptions to this are CDMA "dumb" phones and most smartphones.
For unlisted CDMA dumb/feature phones, MPE+ might be able to have their File System extracted by selecting "Other" as the Manufacturer and "Other CDMA" as the Model in MPE+. Please note that, if this works, it will only extract the raw File System, and will not parse out data.
MPE+ does not support unlisted GSM dumb/feature phones.
For unlisted Android, iOS, and Windows Mobile OS devices, MPE+ includes generic extractions that can be used.