What type combination would you like to see next?

Ground/Fairy

Fire/Fairy could be done if they'd just add it to Kanto Ninetales already to mirror its Alolan counterpart. As for a Type that hasn't been done yet… Fairy/Ground for me. Combine two strong as bleeping heck Offensive Types with Ground that counters BOTH of Fairy's weaknesses. Two immunities(Dragon + Electric) and hits Fire, Poison, Rock, Steel, Electric, Dragon, Dark and Fighting for x2. Resists Rock, Fighting, Bug and Dark(hence Knock-Off doesn't hurt as much… still annoying though) and only takes Super Effective Damage from Water, Grass and Steel(latter of which Ground hits for x2 so Steel/Flying is arguably the best pick to counter it).