There is rarely one right answer. Here are several categories of pairing options, each with a reason it may work.
Turquoise
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Cobalt Green
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Cyan
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Sage Green
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Pewter
Enough lightness contrast to read as two distinct colours without feeling harsh.
Sky Blue
Enough lightness contrast to read as two distinct colours without feeling harsh.
Teal
Enough lightness contrast to read as two distinct colours without feeling harsh.
Powder Blue
Enough lightness contrast to read as two distinct colours without feeling harsh.
Burgundy
A saturated accent from a different hue family for a deliberate pop of contrast.
Tyrian Purple
A saturated accent from a different hue family for a deliberate pop of contrast.
Claret
A saturated accent from a different hue family for a deliberate pop of contrast.
Ruby
A saturated accent from a different hue family for a deliberate pop of contrast.
Black
Meets WCAG AA contrast (8.3:1) for normal text if used as text/background.
Navy Blue
Meets WCAG AA contrast (6.3:1) for normal text if used as text/background.
Midnight Blue
Meets WCAG AA contrast (5.9:1) for normal text if used as text/background.
Prussian Blue
Meets WCAG AA contrast (5.3:1) for normal text if used as text/background.