XD84 on 11 December 2018
I gave it some thought. I think it has a good shot to top this list out of following reasons:
1. It was published at the beginning of the month.
2. In December there are less competition than in November. Therefore the game is getting a lot of attention.
3. Holiday season
4. Those who got a Switch for Christmas without Smash will consider to get the game ASAP.
