Open adverbs are provided in this article. The words listed here are commonly found along with the verb open in sentences. This reference page helps answer the question what are some adverbs that describe or modify the verb OPEN.
actually, automatically, barely, carefully, certainly, completely
daily, directly, easily, eventually, finally, freely
fully, generally, gently, gradually, hardly, immediately
merely, necessarily, nightly, officially, partially, possibly
probably, properly, quickly, really, scarcely, simply
slightly, slowly, suddenly, surely, usually
Hope this word list had the open adverb you were looking for. In addition to adverbs used with open, other example verb adverb pairings can be found on this site.
You can help by adding more adverbs in the comments. Thanks.