I can recommend https://freesound.org/ for sound effects. They have the most amazing sound effects for free (most with CC Attribution licence). Licenses are explained on the site. Nearly all sounds can also be used in payed games, you don't have to pay fees. And I don't mean "beep" and "boop" sounds, but amazing "swamps at night" registered live, "real storms", "blacksmith working" and so on. I've used this site for all of my games.