When trying to avoid repetition in writing, it's important to have a variety of synonyms at your disposal. For the phrase "are one of," consider replacing it with "are among," "belong to," "constitute," "comprise," or "form part of." Additionally, you might use "represent," "make up," "fall into," or "stand with" to convey the same idea. It's important to choose the most appropriate synonym for your context, taking into account the connotation and nuances of each option. Varying your language with synonyms is an effective way to keep your writing interesting and engaging for your readers.