If there are ROMs/ISOs of classic games you want to play, you probably want to download them sooner rather than later.
It's never going to be impossible to find, for example, a ROM of Pokémon Blue, but it's probably going to get more annoying as time goes on.
If you find a good site to download classic games, keep it to your damn self. Tell folks through DMs, don't post.
Make it a priority to download the shit absolutely nobody else has heard of or would pay attention to. We're more likely to lose Medical 91 and DamDam StompLand (assuming neither game becomes a Hidden Gem™, that is) than we are Majora's Mask. Your download could very well be what prevents them from sinking into the wide womb of uncreated night.