Great suggestions, everyone! Let's keep the list updated:
1) Trophies for winners of tournaments/leagues. Mouse-over text will state the specific competition, e.g., "Gunboat 2014 Champion".
2) Gear icon for contributors to the code-base (like how VDip gives variant creators a gear icon). Maybe have bronze, silver, gold levels.
3) Gold, silver, bronze ghosts updating monthly for the top 3 GR leaders.
4) Gold, silver, bronze battleships updating monthly for the top 3 gunboat GR leaders.
5) Iron fist for the "most oppressive" moderator. This can be decided by a rolling community vote.
6) Care bear for the "friendliest" moderator as decided by rolling community voting.
7) Dunce hat for the most idiotic forum posters as decided by rolling community voting.
8) Bleeding heart for the most vocal political activists on this site. I figure being labeled by this icon would piss off both the liberals and the conservatives.
9) Ban-hammer for the moderator that had banned the most players in the preceding month.
10) Pentagram for the most vocal Christian proselytizers.
11) Cross for the most vocal atheists.
12) Everyone gets their zodiac sign, both Chinese (e.g., goat, dragon, ox, rabbit, etc.) and "Western" (e.g., cancer, scorpio, virgo, etc.)
13) KKK hood for the most racist member.
14) Gold star for tournament directors. How about a black and white checkered flag instead? Or maybe the black and white vertical zebra stripes (like for American football refs)?
15) Icon for reliable members. Maybe a clock (in the style of the Swiss railroad clocks)?