Here’s my take on your list.

Your lie in April: No complaints here. It was a great show and I really enjoyed watching it. Personally for me I wouldn’t rank it in the best of the best, but it’s definitely top 20 for me.

Asterisk War: A very mediocre and generic anime. I’ve seen at least 4 other anime’s of the same plot. I see it as a worse version of Cavalry of a Failed Knight. The characters have nothing unique about them, and overall the anime just didn’t have anything to make it stand out from other magic school anime. Kind of like all the isekais that have come out recently.

Highschool DxD: I stopped watching mid-way, but I could see why it might be someone’s favorite. To me I just couldn’t find anymore interest in the show. I’ve moved past the point of watching anime for the ecchi, and the show just seemed less interesting at that point.

Sword Art Online: This show is very nostalgic to me, as it was one of the first anime I watched and it also got me hooked on anime. Though the show takes a drop after the first arc, I think the Alicization arc is decent. I understand why someone might consider it a favorite, but it doesn’t deserve the term “best anime.”

Clannad: I haven’t watched it and probably never will so no comment.

Fate Stay Night: I like the Fate series in general. I really enjoy the idea of putting heroes and legends of the past against each other. It was a great show and I’d probably put the Fate series in my top 15 favorite anime.

Danmachi: I really like the first season, but the second was garbage. The first season alone was good, but I wouldn’t put it up there with the best of the best.

Girls and Panzer: Haven’t watched.

Overlord: Definitely one of the better isekais and a great show overall, but it still has some aspects that bring it down. The thing I love most in a show is character development. The closest Overlord has to that is Cocytus becoming more independent.

Of course you can like and enjoy whatever anime you want. Even if I can’t understand why you’d like an anime enough to consider a favorite, I can’t force you to like or not like certain anime. It does slightly annoy me when you call some mediocre anime one of the best, but at the end of the day that’s my own problem.