There is rarely one right answer. Here are several categories of pairing options, each with a reason it may work.
Rust
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Copper
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Ochre
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Sienna
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Burnt Sienna
Enough lightness contrast to read as two distinct colours without feeling harsh.
Vermilion
Enough lightness contrast to read as two distinct colours without feeling harsh.
Terracotta
Enough lightness contrast to read as two distinct colours without feeling harsh.
Tomato
Enough lightness contrast to read as two distinct colours without feeling harsh.
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.
Ivory
Strong lightness contrast and saturation for a bold, graphic pairing.
Grey
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.
Silver
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.
Lime
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.
Chartreuse
A saturated accent from a different hue family for a deliberate pop of contrast.
Cyan
A saturated accent from a different hue family for a deliberate pop of contrast.