There is rarely one right answer. Here are several categories of pairing options, each with a reason it may work.
Dark Orchid
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Ultramarine
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.
Blue
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.
International Klein Blue
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.
Charcoal
Enough lightness contrast to read as two distinct colours without feeling harsh.
Black
Strong lightness contrast and saturation for a bold, graphic pairing.
White
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.
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.
Peridot
A saturated accent from a different hue family for a deliberate pop of contrast.
White
Meets WCAG AA contrast (6.0:1) for normal text if used as text/background.
Ivory
Meets WCAG AA contrast (5.9:1) for normal text if used as text/background.
Mint Cream
Meets WCAG AA contrast (5.8:1) for normal text if used as text/background.
Azure
Meets WCAG AA contrast (5.8:1) for normal text if used as text/background.