Mods don't always show in the mod list

I’m certain I put them in correctly, but for some reason the new mods don’t appear to show in the mod list for creating a new world. I thought that perhaps they are just going in the game automatically? I put it into the mod folder, and made sure the folder with the mod info was not in itself (since unzipping does that at times). I’m not sure if it is working or not, but I’m hesitant to say it is.