Ken

• Same eraCurtisLike Ken, it was given most in the 1960s.#984 · falling
• Same rhythmLevSame beat as Ken: one syllable, ending on a consonant, but it starts differently.#999 · steady
• LongerKabirTwo syllables to Ken's one: a long name beside a short one keeps them distinct.#999 · steady
• RiskyKoenOne letter away from Ken. You'll call the wrong one for years.#622 · rising

Suggestions come from names in this year's top 1,000. Rhythm and rhyme are judged from each name's pronunciation (Wiktionary's, or espeak's reading of the spelling), so a few calls may be off.