There are many DX7 patches available online that are compatible with the TX-216. Here are some here at Synth Zone at http://www.synthzone.com/midi/yamaha/dx7/

There are literally 1000s of sounds here, so the big job will be trying to find which ones you want. Some sysex programs expect the file extension to be .syx but you will find other extensions which may require those files be renamed to .syx

Midi Ox is probaby the best software to download and install for sending sysex banks to your TX-216. http://www.midiox.com/