There is rarely one right answer. Here are several categories of pairing options, each with a reason it may work.
Purple
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Tyrian Purple
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Eggplant
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Indigo
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Dark Orchid
Enough lightness contrast to read as two distinct colours without feeling harsh.
Mulberry
Enough lightness contrast to read as two distinct colours without feeling harsh.
Blue Violet
Enough lightness contrast to read as two distinct colours without feeling harsh.
Slate Blue
Enough lightness contrast to read as two distinct colours without feeling harsh.
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.
Spring Green
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.
White
Meets WCAG AA contrast (9.6:1) for normal text if used as text/background.
Ivory
Meets WCAG AA contrast (9.5:1) for normal text if used as text/background.
Mint Cream
Meets WCAG AA contrast (9.4:1) for normal text if used as text/background.
Azure
Meets WCAG AA contrast (9.4:1) for normal text if used as text/background.