Spell adverbs are provided in this article. The words listed here are commonly found along with the verb spell in sentences. This reference page helps answer the question what are some adverbs that describe or modify the verb SPELL.
barely, clearly
correctly, hardly
necessarily, rightly
scarcely, usually
Hope this word list had the spell adverb you were looking for. In addition to adverbs used with spell, other example verb adverb pairings can be found on this site.
You can help by adding more adverbs in the comments. Thanks.