> You're not allowed to use Pikachu commercially.

There are many uses of "Pikachu" that are reserved for the trademark holder, but by-and-large the point of trademark is to avoid consumer confusion by preventing people from passing off goods/services that aren't from the "Pikachu" holder as actually being from the "Pikachu" trademark holder.

Generally, I am allowed to use "Pikachu" if it's in reference to Pikachu and doesn't involve passing off non-Pikachu things as actually being Pikachu things. If I'm a former employed-by-Nintendo Pikachu illustrator, I'm allowed to advertise that. (Even if I can't provide samples of my work.) I can advertise that I'm the "#1 seller of Pikachu snuggies" as long as I am the #1 seller of non-counterfeit Pikachu snuggies. I can charge people a subscription fee for full access to a website where I review Pikachu (and other pokemon). If I work at Walmart and someone asks me where they can get a Pikachu plush, I'm allowed to direct them to the Digimon plush section, for which I receive a kickback on sales.

The consumer confusion happening when someone googles a trademark and gets ads for different things isn't due to trademark infringement, it's due to misleading ads, which shouldn't be allowed regardless of whether a search term is trademarked or not.