As an
Karate skilled person I am always interested in other martial arts. Some of the most successful martial art forms are listed below. If I should pick a favorite then it would surely be Russian
Sambo and mixed with Israelian
Krav Maga.

Savate - a fighting style which involves more kicks than any other martial art. Savate has french origins and was practiced as a timekiller among the french sailors to devour time when on board a ship. In Savate it is common to make use of what ever you can hold on to - to assure your foothold. Which means that you can practice Savate drunk - to a certain degree. Savate is fought with shoes on and specifically with steel enforced toe tips. Savate is a medium range martial art.

Krav Maga is an Israelian martial art. Krav Maga is very brutal and the key to this art is getting your opponent to the ground and out of condition to continue. Krav Maga is especially target against combat where there is little room. Krav Maga is also a martial art which does excellent against armed counterparts. Krav Maga let you utilize targets as throath, eyes and other very soft tissue spots. Very brutal and very fierce. But less useful against martials arts where space is of essense like Tae Kwon Doo.

Sambo is a martial art which origins from Russia. Sambo uses a mix of strikes, kicks and submissions. Sambo is a brutal art form and it is extremely practical. One of my absolute favorites. Sambo can be use in close combat aswell as longer range fighting like Savate. Sambo is also one of the martial art forms which has proven to be a successful martial art as it several times has proven superior in the Octagon at UFC. If you ever consider practical fighting then look towards a Sambo training facility. Sambo is also good against armed counterparts.

Pradal Serey originates from Cambodia. The style is like Muay Thai just more brutal. Pradal Serey is most known from the movie
Bloodsport, where Jean-Claude Van Damme's final fight is against a Pradal Serey fighter. Pradal Serey utilizes knees, elbows aswell as feet and hands. Pradal Serey is not known for it's submissions as it is a striking and kicking martial art form.

Silat originates from Malaysia. Silat is fierce and brutal martial art form. Silat is an attack-first combat form, it is not a passive form like Aikido or other more reaction based martial art forms. Every Silat move has a counter move and most Silat moves open up a vide range of finishing moves to bring your opponent down.