Morrigan sits next to 4 phonetic neighbors — Morgan, Moira, and Imogen are the closest matches by sound. Most share Morrigan's Irish-rooted cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"great queen"
"be well, be alive"
"warrior hound"
"noble, bright"
"radiant, sun"
"grace, divine favor"
"broad island (alternative etymology)"
"rowan tree"
"honor, esteem"
"light, bright one"
"helmeted chief"
"bright, shining one"
"universal strength"
"high, noble, strong"
"beautiful, lovely"
"pleasant, beautiful, radiant"
Similar sound: These names share phonetic patterns with Morrigan — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old Irish origins, giving them the same cultural heritage as Morrigan.
Rhythm: Morrigan is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.