Players. I mean world of warcraft players make their own database of ninjas and trolls for raids I don't see why we can't start black listing players ourself and start a data base.
Riot doesn't want trolls called out on forums for w/e reason so I say we make a website and do it , if you troll a game on person, feed on purpose or toxic then you are black listed with a description of what you did that game. As time goes on your people who play with that person can either upvote or downvote them as a player.
So for instance lets say I'm in champ select and I type in my team mates names and one of them comes up with a red flag because he has been reported multiple times by players. This gives me two options.. one I can dodge or two I can make sure to watch that lane so he doesn't feed/troll etc.
It's a team game and you should be given then option or at least data of your team mates who troll. LoL king works but you don't have enough time to look over every player, know why he was 2-13 as adc rather it was trolling or he had two afks or trolls.
me and my friends have a small data base where if we get a horrible player or troll we put them in it, that way if we come across them in a future ranked game we can give the team a heads up with what they are gonna deal with and have the option to dodge or put up with it.
It's saved me some losses i know that much.