Oskar sits next to 4 phonetic neighbors — Oscar, Oskar, and Oliver are the closest matches by sound. Most share Oskar's Scandinavian cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"divine spear, god's spear"
"greatest stream (via Maxwell)"
"God is gracious"
"follower of Dionysus, god of wine"
"home ruler, lord of the house"
"carrier of the anointed one"
"gracious defender"
"just, righteous, upright"
"from the Roman gens Terentia"
"cellar keeper, wine steward"
"sun, lord"
"dark, black-haired"
"crown, wreath"
"bright-headed warrior"
"free man, strong man"
"invented name; possibly son of the fearless one"
"peace power"
"yew warrior, bow warrior"
"red-haired, little redhead"
"God is gracious and humble"
Similar sound: These names share phonetic patterns with Oskar — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old Norse ás + geirr origins, giving them the same cultural heritage as Oskar.
Rhythm: Oskar is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.