Quite a few suggestions for what to add, some obviously more viable than others. Keep up the good work tho:)
Stall breakers: Landorus-T (its Earth Plate smack down set when adamant 2hkoes unaware clef, also gets up rocks vs stall and generally pressures stall)
Walls: Phys Def: Celesteela (to check Pinsir, FlyniumZ LandoT)
Defog: M.Latias (phenomenal bulk, paired with nice speed, and utility and ability to escape pursuit with reflect type)
Leads: Aerodactyl (faster than current leads, can set up tailwind too, has fire coverage)
Zmoves: GrassiumZ Kartana (stall breaker set), DragoniumZ Latios (now offensive cm sets are becoming popular), GroundiumZ Weavile (innovated by Hayburner to lure Magearna), SteeliumZ Zygarde (lure clefable), BugiumZ Volcarona (allows it to beat Ttar, has become popular recently ?)
Rain: Tornadus-T (hurricane), Tapu Koko Zapdos (thunder)
Something to add in the future perhaps, a terrain setter and terrain abuser (through the use of the terrains effects or moves), though this could cover a lot of pokemons, but I was thinking pokemon that specific calcs are affected (M.Medicham being able to beat M.Sableye) or common abusers or the terrains effects such as Heatran.
Electric: Tapu Koko, M.Diancie Heatran M.Camerupt (nature power), M.Medicham M.Mawile (thunder punch), Hawlucha (seed)
Grassey: Tapu Bulu, Suicune Zygarde (recovery (for vincune)), Heatran Magearna (ground weakening), M.Camerupt (nature power)
Misty: Tapu Fini, Zygarde (both no toxic and dragon weakening), M.Camerupt Heatran (nature power)
Psychic: Tapu Lele, M.Alakazam (priority and damage boost)