Endangered adverbs are provided in this article. The words listed here are commonly found along with the verb endangered in sentences. This reference page helps answer the question what are some adverbs that describe or modify the verb ENDANGERED.
actually, constantly
critically, gravely
greatly, highly
increasingly, really
seriously, severely
Hope this word list had the endangered adverb you were looking for. In addition to adverbs used with endangered, other example verb adverb pairings can be found on this site.
You can help by adding more adverbs in the comments. Thanks.