A snapshot from each season to compare champs that had highest WR, ban rate and popularity and also the general state of the game [Average Duration, Blue vs Red WR, etc.]. :
Season 5] Why the Raptor Buff is So Good - Unappreciated Benefits : r/leagueoflegends
Season 5 Baron Buff Changes - No More Regen. Buffs the Crap out of Minions - YouTube
Banner of Command in 8.4 : r/leagueoflegends
S5 Jungle Cheat Sheet : r/leagueoflegends
New Mini-Baron Monster - Rift Herald - PBE Pre-Season - League of Legends - YouTube
Aphromoo Insane Baron Steal : r/leagueoflegends
S5 Ranked Thread - Goal: Plat :: Page 8 :: League of Legends (LoL) Forum on MOBAFire