I usually start with Food Wishes, Serious Eats, or the New York Times. Julia Child for French food, Just One Cookbook for Japanese food. Budget Bytes when the bank account is looking a little thin. Dessert Person when I have a lot of time and want to knock the socks off my friends.
Kenji is my go to choice for most things.
More niche but I’ll mention the ramen_lord Book of Ramen if you ever want to make homemade ramen (or even just sprucing up instant ramen with authentic toppings).
I recently discovered IndianHealthyRecipes.com, his chicken tikka masala and chicken biryani have become regular favorites at our house.