Season 11 of The Walking Dead brought back the intelligent variant of walkers from Season 1, impressing viewers. In Episode 19 titled "Variant," Aaron's group encountered a new variant of walkers on the road to Oceanside. These walkers seemed to have evolved into a state closer to human intelligence. 

They were able to grab weapons, climb walls, and open doors, posing a new and challenging threat to the survivors. However, these walkers were not as fearsome as the running walkers seen in The Walking Dead: World Beyond.

This variant was not entirely new, as Season 1 of the show had already introduced walkers with problem-solving intelligence.

The survivors were taken aback by this unique problem and had to adapt their knowledge about walkers to survive. The plot left some unanswered questions about where these walkers had been all this time and why they had mellowed out. 

 In the spinoff series, The Walking Dead: Dead City, climbing walker variants were absent, but a new threat called the Walker King emerged from the sewers of Manhattan. It was formed by multiple walkers stuck together and proved to be exceptionally fast and strong.

 In another spinoff series, The Walking Dead: Daryl Dixon, new walker variants called burners and hybrids were introduced in France. Burners had acidic blood that burned the skin of their victims, while hybrids displayed enhanced agility, speed, and strength. Daryl Dixon amped up the excitement with these threatening walker variants.