@jsgehring - OK, I think I got it and we may be close. Here it goes:
1st picture with the four wires with blue tape that don't go anywhere - easy. Leave them be.
3rd picture with seven wire nuts, it looks like the wires coming from the controller have "station #" printed on them. Find the wire that says "station 1" and put it's partner wire in the wire nut in the Rachio zone 1, etc.
4th picture with three wire nuts, looks like it has your 8th zone/station wire. The other two wire nuts are the line input (power) which the Rachio will provide with the barrel plug adapter, so leave those be.
Now the fun and the guess (hey I'm being honest):
2nd picture - the wire nut with black, red, white/green, white/blue, white/red and white wires. This looks like a bundle of common wires. If you follow the white wire back to the Rainbird, I'm betting it goes to the common connection. If the connection and wire is unlabeled, white is usually the common wire color. Either cut the white wire where you can use it to connect to the Rachio or replace the white wire in the wire nut with a wire so there will be only one wire going to the Rachio common port.
Now, the remaining wire nut with green, yellow and white/orange wires. The white/orange wire coming from the Rainbird looks like it has M-V which is Rainbird's standard for Master Valve wire. Just like the white common wire, either replace it in the wire nut with another wire or clip it to connect it with the Rachio's M connector. Don't forget enable the Master Valve option in the Rachio application like @mckynzee mentioned - it is under advanced (I believe). As there are two pairs of wires going to the master valve(s) (black and red along with green and yellow) I believe that is why @gene was thinking there are two master valves in play. If there are any issues, we might need to have pictures of where that wire bundle terminates.
Go wire it up!