Rich purple tones, like plum, are considered royal colours because they were often worn by kings and queens. Cleopatra loved purple so much that she instructed her servants to soak 20,000 Purpura snails for 10 days in order to get just 28.4gr of purple dye. Take inspiration from nature when choosing paint colours that match plum. For a regal and sophisticated colour scheme, look for colours that occur together naturally, especially in plants and flowers.
Yellow is purple's complementary colour. They are located opposite each other on the colour wheel, and each makes the other look brighter when put together. Because plum is a rich jewel tone, a lighter yellow would match it best. Lemon yellow makes plum paint look brighter and more purple, creating a juvenile look. A lighter yellow won't compete with the plum but will accent it nicely.
Orange is richer alternative to yellow. Pairing plum with orange creates a warm, cosy effect because both colours have a red undertone. This colour scheme is in the autumn colour palette, and would look good with gold or bronze accents. The orange you choose could be a bright orange or a burnt red-orange. A light orange colour such as peach would also complement plum paint.
Green is on the cooler side of the colour wheel and contrasts with red-toned plum colours. If your plum paint has a blue undertone, green will also work nicely. The green you choose should be significantly lighter or darker than your plum paint. A dark hunter green would work if the room has enough windows and lighting, otherwise, it might appear cavelike. A light green such as seafoam or sage would complement plum without overpowering it.
White is neutral that matches any colour. Plum paint can look dark but can be brightened with white trim and accents. Consider using white on ceilings and wainscoting to add character to a room. The white could be a pure snow white or a creamy vanilla. If the white has a yellow undertone it will appear creamier and warmer.