I'm not able to run a league as commissioner as I travel many weeks each year but I occasionally come up with some interesting league themes that are the type of league that I like to play in. If you like 'em you can have 'em but let me know so I can join.
1. .500 League Theme - Throughout history there have been only about 75 different teams that ever finished at exactly a .500 winning percentage. In fact, only one New York team has ever had it happen, the 1911 New York Highlanders. The Giants and Mets have never finished .500 and the Dodgers only once, in 1993 while in LA.
.500 teams provide their fans a lot of thrills, enough quality play to not be a losing team, but not quite good enough to be a winning team, either. Might the season have gone another way with only a few differences?
In our league, owners will choose from among the approximately 75 teams in history that have had even W/L records (.500), i.e. the 1993 Dodgers or 1911 Highlanders. Keep 7 players from that team's roster and use that player in that season (minimum of 3 Pitchers must be taken). 1911 Birdie Cree (Highlanders) had a fine season and Russ Ford won 22 games.
The other 18 players can be twisted to any other season in that player's career. You can give your manager the chance to get a, hopefully, far more productive season out of your totally average team. The beauty of it, I feel, is that all the managers will be starting with teams that are essentially completely evenly-matched, they all finished at .500.
Payroll? 80M, 90M?
2. Former All-Star theme:
Pick any All-Star Game and choose your team from players on those rosters. Every player, however, MUST be twisted to another, later, season in their careers and that season must be after the final ASG appearance in their careers. So, you can have Tom Seaver, but only after 1981. Nolan Ryan, post-1989, George Brett post-1989, etc.
Payroll: 80M, 90M?
3. One of These Days Theme:
The same as above but, obviously, each player on your roster has to be twisted to a season prior to his first-ever ASG appearance. So, you can have Brooks Robinson up through 1959, Robin Yount through 1979, Fred McGriff before 1992, etc.
I have several more but those are my favorites. I'd love to see someone make a go of these themes because they're the kinds of rosters I like to build.