Jonas Sckazinski offered this guy for my Azorius Academy vision. In addition to being a champion, he's a lord for the scholar token mechanic that Jonas was suggesting. I do like the design, although I don't know that the tribal element should be a primary mechanic on a plane with Suvnica's guild structure. Also, being a Wizard crowds his type line too much and doesn't really add anything.
lpaulsen offered this guy for Jay Treat's Orzhov (Purity through mass violence). It plays up the mass violence angle through maximizing the value from Day of Judgment effects, and feels both White and Black.
Jules made this one for my Orzhov (Assassins for the betterment of society). A fantastic design, and a nice riff off of Hunter of Eyeblights. I might specify that the counters have to be +1/+1 in the second line, but it definitely looks like a lot of fun either way.
Lobster667 and lpaulsen both designed a legend for my vision (monopolistic exploitation over natural resources).
lpaulsen made this guy:
Nailed it. Two abilities that haven'r really been done before, an elegant package, fits directly into the vision. Fantastic.
Lobster667 made this guild leader:
Something feels a little off about this guy. I think mostly because he in no way rewards you for playing black creatures. All of your green creatures become awesome when he's on the board (probably a little too awesome - there's very little benefit to not immediately wipe your own board for cards and life the second he hits the battlefield) while your Black creatures sit on the sidelines listening to Elliott Smith and feigning apathy. I think that if you just collapsed the abilities and had it skip Zombie creatures in general... "Whenever a non-Zombie creature you control dies, draw cards equal to its power, gain life equal to its toughness, and return that creature to the battlefield under your control. That creature is now a black Zombie in addition to its other colors and types." Still a powerhouse ability, but he cares about at least some of your black creatures and makes you jump through at least one more hoop to reap the awesome.
Lobster667 made this for his own Boros vision (community striving towards individual freedom in peaceful/caring way). Although the keyword abilities doesn't really scream peaceful or caring, he did play up the control element I saw this vision embracing. That said, if your opponent doesn't have some sort of removal, this guy might as well say "You win the game," or, more likely, "The game is a draw." It completely forecloses your opponent from attacking meaningfully, and he can't be killed attacking in unless your creature can deal lethal first strike damage. He fulfills the guild vision of peace, but shuts down the game of Magic that you're playing in the meantime.
The fix that first comes to mind is to keep his third line but limit the damage prevention to combat damage to creatures. If they can still hit you, then the game is still a game. There are probably a number of other ways to make him powerful and interesting without shutting down the game, but that's at least a start.