Rhyder sits next to 3 phonetic neighbors — Ryder, Riley, and Rider are the closest matches by sound. Most share Rhyder's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"horseman, cavalryman"
"air, atmosphere"
"sword"
"of Mars, warlike"
"son of Dick, son of Richard"
"victory, honor"
"unity, excellence, number one"
"third in line"
"eternal, immortal"
"dedicated to Mars (god of war)"
"tree, oak tree"
"bright, shining"
"Geirrapos island, grassy island"
"beloved, darling"
"deer, stag"
"noble born"
"protector of humanity"
"glowing, scorching"
"resolute protector"
"lord of the sea"
"God is gracious (via Hans/John)"
Similar sound: These names share phonetic patterns with Rhyder — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old English origins, giving them the same cultural heritage as Rhyder.
Rhythm: Rhyder is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.