Likely a modern combination of May and Bree.
Maybree is a contemporary American invention, likely created by blending the month name May with the suffix -bree, often derived from Brianna or the Irish name Bree. It follows the trend of creating melodic, multi-syllabic names with a familiar phonetic feel.
Less common today
Maybree isn't in the latest US Top 1000. It last peaked at #5,607 in 2014.
US births per 5-year period, 1990βpresent (SSA data).