They may be used by poets — 10 and 11, for example, or 1 and 6? (3,6)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

KEATS (10) and YEATS (11) are examples of eye rhymes – and they’re both poets! –  and SPRY (1) and SKYE (6) both rhyme with ‘eye’ (but they’re not ‘eye rhymes’) – brilliant clue!