I'm trying my best to include all noteworthy original WordPress themes maker while keeping the list clean and informative. I constantly do research, but I cannot know it all. You can always help improving the list by suggesting a WordPress theme company by reaching out.
WordPress themes marketplaces with multiple authors like ThemeForest, CreativeMarket or MojoMarketplace sell themes from hundreds of authors who sell exclusively on marketplaces. I try to include theme shops that also sell independently or externally.