While the other one, Kaido & Linlin, is a fun card, it is a bit gimmicky and hard to play
Its not just kids that are driving the resurgence, according to data scientist Eric Louderback
If Clara is the companion to The First Doctor, three +1/+1 counters would go onto a creature or artifact instead of one
The one mana counter for two-drops had fallen out of favor in Modern in recent years after being a staple a decade ago, but currently 40% of the top ten creatures in Modern are two-drops as cards like Drannith Magistrate (planeswalker stamp), Orcish Bowmasters, Amped Raptor, and Ajani, Nacatl Pariah see heavy play
Exert Influence: in Standard this can be a great way to take over a Wall
Its still worth running, of course, but its often playing second fiddle to more robust drain engines, like Bastion of Remembrance