Yes! Man, we had some killer games in 75! Other rivals from 75's IFC North division: Lellow and Mardn.

Other GM's I'd consider rivals are Macrovil, MWD, and Michael77, mostly because I can't beat them. And Bryson, because, I never win that game, but who does?

But my favorite rival is Big Poppa, we clash in NCAA as Oklahoma/Oklahoma State. I think I may have won more games, but Poppa dominates me in the trash talk game. His GIF skills are OUTSTANDING...

OK - serious question. What era do you want this league to start in?

1973 - Start of the Oakland - Pittsburgh rivalry.
1992 - Start of the Dallas - San Fran NFC domination

Others?

Given the current state of code, 1940s might jibe with the stats.

I thought of making the league with the defunct teams, but I like the current pro teams more: https://en.wikipedia.org/wiki/List_of_defunct_National_Football_League_franchises

I would love a league like this, it would bring out the realism in gameplay, it would definitely get those competitive juices flowing