Actually, I do not really think that there is a really similar series to the Hunter × Hunter. At the beginning I did not really enjoy it, however after a couple of series I understood that it is actually really awesome. Haikyuu is also good, however it is not that even close to HunterxHunter. Actually, almost everything out of this series is different compared to any other anime. That is what makes it so great and so special. Actually, after watching it, I got me thinking a lot about the waifu feature, and recently I found the
https://waifuforlaifu.com/. I was actually surprised to find such a thing, it is rather great actually.