Yu-Gi-Oh! GX! It may seem silly and mundane at first, but season 3 has some amazing storytelling and deconstructs many shounen troupes in interesting ways.
Also, the main character is canonically lgbt! His endgame love interest is an enby, though they are referred to with she/her pronouns in most localizations :]
I can't believe no one already suggested this, but the melancholy of Haruhi Suzumiya was very popular. All I can add is there's 2 watch orders so I suggest you read online about the two of them and pick the one you prefer(Albeit I recommend the original broadcast order which only includes season one, then watching the chronological one which is both season 1 and 2. But as I stated prior it's up to you :P)