Alexander is really good, one of my favorites. I prefer to make it with Brandy/Cognac like the recipe I linked, but you can also make it with Gin for a different, stronger flavor.
Grasshopper looks and tastes like chocolate mint ice cream. If you like that flavor enough to want an alcoholic version then go for it.
Favorites for this season are Pseudo Harem ED, Oshi no Ko S2 OP and Tower of God S2 OP.
Honorable mention to the Nokotan OP for the memes, and for the evolving credits for Tower of God S2, really like how they are a "season so far" summary.