I actually used a Mono-Ice team for a while. I really enjoy using Ice-Type moves! If I were to make a Mono-Ice team now, I think I'd include Alolan Sandslash, Froslass, Weavile, Vanilluxe, Glaceon, and Lapras. (I'd be inclined to use Vanillite instead of Vanilluxe if it had also gotten Snow Warning.)
Realistically, based on my current hobbies, I think I'd be a Bug-type trainer. My bug team may look something like this: Dunsparce, Mothim, Shedinja, Yanma/Yanmega, Flygon, and Volcarona. Although they're not all Bug-type, they're all based (at least partially) on insects. (Including solely Bug-types, I might use Mothim, Shedinja, Yanma/Yanmega, Volcarona, Shiny Mega Beedrill, and Forretress.)