I've been playing solitaire electric football since 1963. I developed a league with 6 teams in 1966. Since then, i've expanded my league to 10 teams, 12 teams, and now 16 teams over the years. Each team consists of 54 players plus kickers and punters and have home and away jerseys. The league is divided into 2 conferences of 2 divisions with 4 teams in each division. Playoffs consist of 4 division winners plus 1 wildcard from each conference (best record within the division not counting the division winners). The division winners with the best record in each conference get byes, and the wildcard and the other division winner within the conference play. The winner of those games play the bye team in their conference. Then the conference winners play for the championship in the Super Bowl.
I have developed my on set of rules using dice rolls to determine offensive/defensive formations and run/pass and blitz/coverage packages for each down by team using a multi-stop system. It seems to work well for me. It takes a long time to play a season (3-4 years) as I play using a 30 play quarter (not including plays out of bounds, incomplete passes, penalties, etc, which would stop the clock normally. I realize most would think 3-4 years is a long time, but it works for me. I keep individual statistics for each player on each team (starters, backups, special teams) using spreadsheets for each team. Also track individual players throughout their careers in my league using spreadsheets to record their stats. My current teams are made up of "all-stars" by team who played between the years 1960 to 2000. It's fun watching players such as Troy Vincent covering Bob Hayes, even though they didn't play against one another. Also, I enjoy looking at the stats for players over their careers in my league. Just my 2 cents.