A confident, deliberately saturated frame colour (navy, burgundy, green and similar are common).

A saturated frame colour like this sits directly beside the eyes, so it becomes one of the strongest colours on the whole face — worth choosing deliberately rather than as an afterthought.
The black studio background dominates a raw automated scan of this photo — this palette was reviewed to represent the frame's actual bright green colour, which occupies a small part of the frame."Sonnenbrille gruen" by Tetzemann, CC0, via Wikimedia CommonsFrames sit close to the eyes, so a saturated colour here can become the strongest colour on the whole face — genuinely worth being intentional about.
Less versatile across outfits than a neutral frame, but a deliberate way to make eyewear a statement.
Can either echo or deliberately contrast the eye colour; both are legitimate approaches.
Browse eye coloursWorks best considered alongside hair colour as part of the same near-face palette, not in isolation.
Browse hair coloursA neutral metal (silver or gold, whichever already suits the wearer) often balances an already-bold frame colour. Compare metals.