Alonso sits next to 3 phonetic neighbors — Alfonso, Alonzo, and Antonio are the closest matches by sound. Most share Alonso's Spanish-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"noble and eager, ready for battle"
"supreme, of highest rank"
"appointed by God"
"gift of God"
"who is like God (rhetorical — no one)"
"from Mauritania, North African"
"hater of injustice"
"protector of people"
"staff of the Goths"
"of the Frankish people"
"saints, the holy ones"
"glory of the land"
"brave with a spear"
"little warrior, young Mars"
"powerful ruler"
"lover of horses"
"illustrious, famous"
"blessed"
"greatest one"
"noble bright (adal + beraht)"
Similar sound: These names share phonetic patterns with Alonso — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Germanic via Visigothic origins, giving them the same cultural heritage as Alonso.
Rhythm: Alonso is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.