Nixon should definitely definitely be in there. The atmosphere on the Kippax that day was electric. The City fans' sense of injustice at the sending off was comically misplaced too. Nixon totally did Bright. Steve Redmond put an equally comical performance in nets that day following the dismissal. That 3-1 loss put an end to a promising run from our inexperienced, but talented team.
I think Andy May deserves a mention. Towards the end of the 1984/5 season iirc. The ref had a meat and potato pie thrown at him iirc. I think it was a 0-0 draw v Oldham.
The Trevor Francis one was completely justified, although it has to be said it was the campest headbut in sporting history. I'm pretty sure Francis had been advertising the game on Piccadilly Radio earlier that week. Another stroke of marketing genius from City under Swales.
The Pointon one was pretty clear cut too, but hilarious. The Curle penalty that followed it one of my favourite Derby moments.
As others have said Horlock should be in there. Yet another low point that season. I was living near Bournemouth at the time, so at least I didn't have far to travel home. It's funny how that season seems great fun looking back, but I'm pretty sure it didn't feel that way at the time, at least up until Christmas.
Stuart Pearce v Norwich in 2001/2 also deserves a mention, if only for the tub-thumping performance that followed it. Brilliant day.
Coton's v Derby really sticks in the mind too. Not only for Quinn's penalty save that immediately followed it, but also for the subsequent corner which the big fellah just plucked out of the air like a seasoned goalie. That broke Derby as much as the penalty save, I reckon. His Gaelic Football skills put him a serious notch above the aforementioned Redmond in nets, that's for certain.
What about Mike Doyle when he was sent off with that dirty rag Lou Macari in a Derby in 1974? I think they both refused to leave the pitch following the dismissal and the ref took the rest of the players off the pitch until they did.
Zaba in the 2013 Cup Final deserves an honourable mention too. I think he and Kevin Moran are the only two players to have achieved that feat (could be mistaken though).
There's nothing like a sending off to really get the juices flowing, especially if there's a sincere (if misplaced) sense of injustice that stems from it.