What would best complement my aikido?

I've been taking Aikido for almost a year now and have found it to be a mostly pive art. The form I study is closer to Daito-Ryu Aiki-Ju-Jutsu (where Aikido and Judo came from), so it's a bit more aggressive than most other forms of Aikido. If you study a more pive form, I'd look into something more aggressive as far as striking and ground fighting. Kickboxing is a great compliment, but I'd get into MMA which incorporates a lot of Muay Thai, Kickboxing, Boxing, Wrestling, BJJ, and Judo. You need to learn to fight on the ground. BJJ is good, but it's mostly submissions, Ju-jutsu (Japanese form) is great as it is a combination of submissions, grappling, striking and weapons, Kickboxing is good for stand up only, Systema is good, but there is a lot of hype behind it and have found it to be not much different than Krav Maga, Tai Chi is more a form of meditation than a martial art, Kendo is good if you're going to be defending yourself with a long object, I don't know what Kiaido is unless you mean Iaido which is good if you want to become a master with a sword, and Dim Mak isn't a martial art, but is rather a concept and sets of techniques in martial arts which concerns itself with debilatating and lethal blows. Hope this helps.