Use the NEC1.irp file. Make a full set with device=210.108 and a second full set with device=210.109

I'm pretty sure that will cover all commands the TX-SR805 can understand.

In the many CCF files I've downloaded, Onkyo uses a mixture of NEC1 and NEC2 protocol. But you don't need to test NEC2. The difference between NEC1 and NEC2 only matters for commands with incremental operation (Vol+, CH+, etc.) not for discretes. Even where the difference matters, testing with just NEC1 would tell you the basics of what the command would do in NEC2.

For receivers (TX-????) Onkyo mixes device codes 210.108 and 210.109. Even though they use fewer than 256 total commands, they spread those commands through those two sets of 256 possible signals.

For CD's (DX-???? or CD-????) Onkyo uses device code 210.44

For DVD's (DV-????) Onkyo uses device code 210.43

I don't know Onkyo model numbering better than that. Some Onkyo devices in CCF files appear to be combo devices (such as CD and receiver). If you have something like that, you would need to try more than two sets of 256 commands.