Synonyms that are in the dictionary are marked in green. Synonyms that are not in the dictionary are marked in red.
Antonyms that are in the dictionary are marked in green. Antonyms that are not in the dictionary are marked in red.
It also offers adventure books, like Candlekeep Mysteries, which DMs can use to run campaigns.
Source: https://www.cnet.com/tech/services-and-software/best-online-tools-for-dungeons-and-dragons/