What I've met so far in Season 6 (High Plat/Low Diamond games)
Silver Border: Instant giveaway of the DQ boosted player (OP.GG everyone quickly). If you see them in your High Plat teams, just dodge. The round is pointless, this player will lose it for you.
Fiora/Riven Picks: This blows your mind, correct? However, this is sadly true. Players generally pick Fiora/Riven when they have no clue how to play top lane and I Guarantee you they will feed their lane. They will push into the turret, ask for ganks, not ward, and get obliterated.
Teammates who type in Champ Select (are fuckin worst): They are the ones who Tilt the most and will (a) AFK in your game or (b) Type more than anything else and end up losing an easy match. If champ select chat is clear as day, then you are good to go.
Wrong Runes/Masteries: There is NO EXCUSE in Ranked. This is a 99% Losing round. Enjoy the 20 LP loss. Nothing you can do.
"I don't play this role": This is also a losing round and typically Gold 5 or lower DQ boosted player, have fun watching this player go 0/15 under 20 minutes. Dodge immediately.
Draven Picks: Instantly OP.GG this player, if he doesn't main Draven, DODGE THE ROUND! They are a guaranteed Tyler1 wannabe and will feed on purpose.
"I am smurf": Just dodge.
Kennen ADC: No, just No. Don't waste your time.
Full AP team: Possible to win with, I highly recommend dodging these games. We are not pro players and cannot make it work in regular Ranked games. Dodge it.
Patch 6.16 - Irelia/Gangplank/Jhin on their team, dodge, it'll be so much easier. Ban those until they are nerfed. Otherwise, play safe and ban.