If you're looking for anime similar to FLCL, you might like these titles. All recommendations are made by Anime-Planet users like you!
Kamba and Shouma Takakura have taken care of their sickly younger sister Himari since their parents disappeared years ago - that is, until the day she died. But as the boys grieve by her hospital bed, Himari sits up, adorned with a strange penguin hat. Suddenly, the three of them are transported to a vibrant world where the hat, using Himari's body as a puppet, charges these brothers with a task: find the Penguin Drum and their sister's life will be saved! Now aided by some odd penguins they received in the mail, the duo must find this mysterious item or risk losing the sister they care for so much. However, they aren't the only ones with their sights on the Penguin Drum, for new enemies await them around every turn, all connected in ways they would have never imagined...
FLCL uses both a great visual and musical performance to entice the viewer into watching more. And boy does it deleiver. Mawaru Penguin Drum is the same in the sense that it's both a visual and musical expereince which shouldn't be missed or ignored. Both have the aura of being wacky and sensible but in different takes and doses. If you like one you'll be certain to enjoy the other.
Terulus: a world destroyed by a haywire terraformer where destructive earthquakes, constant danger and wildlife mutations are a fact of life. Those who survived built giant mobile cities to withstand the tremors, and pass the time with dangerous, no-holds-barred races – the same races that caused the famous champion Loser King to go missing a hundred years ago. Determined racer Shiro Tomoe wants nothing more than to live up to the Loser King's legend, but a terrible accident leaves him nearly dead – that is, until Tomoe, an inventor with her own motives, replaces his heart with a prototype engine. Now, Shiro's performance is tied to his very heartbeat, and success, or failure, will determine his fate.
Some of the color usage in Tailenders reminded me of FLCL's composition. While the stories are nothing alike, the vibrant colors and odditties were. Towards the end one of the characters even resembles the tv-headed guy from FLCL. If you like one, I'm pretty confident that you will like the other.
AD 2019: the giant mecha known as LINEBARREL falls to Earth, grabbing the attention of the anti-machina organization JUDA. Before JUDA can arrive on the scene, an unfortunate accident occurs: LINEBARREL crashes into Kouichi Hayase, a weak and frail pushover of a boy. Waking up underneath a beautiful naked woman, Kouichi discovers that he now possesses great power and can summon LINEBARREL for his own purposes. All Kouichi has wanted is to become a hero of justice and hold his own, instead his childhood friends Yajima and Risako fighting his battles for him – and now he finally has that chance. With LINEBARREL's power, Kouichi becomes cocky and aggressive, lashing out at those he cares about most; and as a 'hero of justice', Kouichi must find his new place in the world and protect himself from two organizations who want their hands on LINEBARREL.
Four months ago aliens invaded Earth, but they're not obliterating cities or abducting huge amounts of people. Instead, they send one single alien to the surface each day and, for reasons unknown, teenager Kakashi is the only person in the world who can fight them. However, this duty takes a huge toll on the boy's psyche, and after a while his memories have all but disappeared. Only his broken cell phone is there to remind him of the life he left behind, but Kakashi is afraid to fix it - for what if there are no new messages, and nobody cares that he's no longer around?
Under the veneer of Action! Aliens! Wacky! in both of these titles is an emotionally nuanced tale about growing up, feeling lonely, that sort of stuff.
They both sport some pretty experimental art styles as well, and gave me a similar feeling in general, so check one out if you enjoyed the other.
FLCL and Kyousougiga are two of those anime which you watch and think, "I'm not quite sure what just happened, but that was awesome!" They both contain moments of purely insane comedy set in a slightly warped reality, but also rely on touching emotional moments to build and flesh out their characters. If you like crazy, you'll find it here.