There is rarely one right answer. Here are several categories of pairing options, each with a reason it may work.
Sage Green
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Brass
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Pistachio
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.
Olive Green
Enough lightness contrast to read as two distinct colours without feeling harsh.
Avocado
Enough lightness contrast to read as two distinct colours without feeling harsh.
Ecru
Enough lightness contrast to read as two distinct colours without feeling harsh.
Forest Green
Enough lightness contrast to read as two distinct colours without feeling harsh.
Ash Grey
A low-chroma neutral lets the original colour stay the visual focus.
Grey
A low-chroma neutral lets the original colour stay the visual focus.
Silver
A low-chroma neutral lets the original colour stay the visual focus.
Taupe Grey
A low-chroma neutral lets the original colour stay the visual focus.
Blue
A saturated accent from a different hue family for a deliberate pop of contrast.
Ultramarine
A saturated accent from a different hue family for a deliberate pop of contrast.
Navy Blue
A saturated accent from a different hue family for a deliberate pop of contrast.
Indigo
A saturated accent from a different hue family for a deliberate pop of contrast.