There is rarely one right answer. Here are several categories of pairing options, each with a reason it may work.
Blue Violet
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Amethyst
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Slate Blue
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Fuchsia
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Purple
Enough lightness contrast to read as two distinct colours without feeling harsh.
Medium Purple
Enough lightness contrast to read as two distinct colours without feeling harsh.
Indigo
Enough lightness contrast to read as two distinct colours without feeling harsh.
Byzantium
Enough lightness contrast to read as two distinct colours without feeling harsh.
White
Strong lightness contrast and saturation for a bold, graphic pairing.
Black
Strong lightness contrast and saturation for a bold, graphic pairing.
Mint Cream
Strong lightness contrast and saturation for a bold, graphic pairing.
Off-White
Strong lightness contrast and saturation for a bold, graphic pairing.
Taupe 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.
Graphite
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.
Lime
A saturated accent from a different hue family for a deliberate pop of contrast.
Chartreuse
A saturated accent from a different hue family for a deliberate pop of contrast.
Yellow
A saturated accent from a different hue family for a deliberate pop of contrast.
Yellow-Green
A saturated accent from a different hue family for a deliberate pop of contrast.
White
Meets WCAG AA contrast (5.7:1) for normal text if used as text/background.
Ivory
Meets WCAG AA contrast (5.7:1) for normal text if used as text/background.
Mint Cream
Meets WCAG AA contrast (5.6:1) for normal text if used as text/background.
Azure
Meets WCAG AA contrast (5.6:1) for normal text if used as text/background.