Wind and brass stands are specialized supports designed to hold your instrument securely when they are not being played. Look for good stability and make sure the sections of the stand which come into contact with you instrument are padded in order to avoid damaging your instrument. A good stand will prevent damage to your instrument by holding it securely, offer a safe place to put the instrument during practice, rehearsal or performance when you may need to swap from one instrument to another, and can help maintain the instruments condition by preventing any undue stress on the body of the instrument and the key and valve mechanisms. I also think that, especially for wind and brass instruments, leaving your instrument on a stand helps it dry after use.
Some of the stands have quite fragile legs, which is why for example, I prefer the K&M 152/3 to the K&M 15232 Compact Flute Stand, but the compact models do fold down to a really small size which can be a consideration when travelling. (Double bass players will snigger at that!)
If you need stands for multiple instruments, Hercules have some of the best offerings on the market.