Brown pants can have some limitation with the colors. Despite this, there are many colors that can be worn with brown pants. The color palette depends on what the wearer's intention is.
One rule to follow is to avoid wearing darker shades of color. The exception to this is if the darker color is a type of brown. Another note is that black is normally considered a color to avoid when wearing brown. The only time black and brown are acceptable is when black is in a pattern with the brown. Wearing red, yellow and orange can come across as being fall themed. Forest greens should be avoided as well because it may give the impression of a tree. Unless these are the intentions, it is recommended to avoid these colors.
A few colors that can be worn as a top would be beige, cream, tan, mint green, browns and pale yellow. If the colors are pale or very light, then most likely they can be worn with the brown pants. Patterns can also be worn with brown paints. They do not have to have brown in the patterns. If there is doubt, wear a pattern that has brown within it. Shoe colors that will work best are brown, gold, beige, tan and cream.