Bokurano: for those times you are just feeling too happy and want to get brought down a bit. Didn’t watch the anime,but read the manga and saw the OP, its great!

Gargantia on the Verdurous Planet: more laid back, but serious back story. A pilot from a total militaristic dictatorship lands on a water world and learns normal life from the ship inhabitants.

Blue Gender: similar setup as Gargantua, but more serious and in the other direction. Normal person in deepfreeze gets awakened in a militaristic space station after earth got overrun by bugs. Now he must adapt to the new world and society he lives in. Similar to starship troopers in some ways. But no humour here.

VanDread: much more humorous: men from a society of only men meet female pirates from a planet of only women. Besides the echi premise, they surprisingly use the setup for more than only ranchy jokes but even explore a bit, what kind of societies could grow from such setups and how would they interact.

Knights of Sidonia: great lore, great visuals, interesting ideas, phenomenally boring main plot and main characters and their dynamics