You can rest assured, the best weapon to use in martial arts (especially in modern times) will always be your hands and your feet. However, if your looking for a more intense sparring session or to put on a “cooler” looking demonstration then you can turn to any of the following weapons to help.
The shinai is used in the Japanese martial art of Kendo. The use of this weapon and fighting style is more difficult than most in that it involves the use of two hands on the weapon and, in general, is a much heavier fighting style. The shinai is almost always made out of bamboo and because of this it is used in only demonstrations because in modern combat the weapon would break very easily, leaving the person using it between a rock and a hard place.
The escrima is a two or so foot long wooden stick that is primarily used in the Philippines fighting style known as Kali but sometimes referred to as escrima itself due to the popular and widespread use of the weapon throughout the discipline. The focus with the escrima is to deliver highly targeted high-impact strikes to your opponent. This is used to help practitioners prepare for an actual knife fight but is still mostly only used in sparring and demonstrations.
You might not recognize this weapon based on it’s printed name but you almost certainly will based on hearing it’s name or by seeing it’s picture. Nunchucks (the american-ized spelling of the name) were originally popularized by the great Bruce Lee. Since then they have become globally popular in many forms of martial arts. Once again, these probably aren’t the best idea for use in a street fight both because they are illegal for personal use in many places and also because they tend to be ineffective against knives and other weapons. Although, they are excellent for demonstrations and sparring because they increase coordination as well as overall form and posture.