Game Modes

ok I have been playing league for awhile and I see these Different Game Modes.....well where are the Other Game Modes, Like (1). Black Market Brawlers, (2). Doom Bots and (3). Nemesis Draft.....Getting Tired of Ascension and Poro King/Hexakill, Shoot Bring back Hexakill on Summoners Rift.......I understand if you want to use the other maps for the Game Modes......let me Suggest Something, How about have the game modes on all the Maps except for Howling Abyss so we can get to choose on what 2 maps we want the Hexakill(mainly Talking about Hexakill) but anyways I want to play some Doom Bots and Black Market Brawlers

Thx Riot c: