where can i get free textures that i can use in a game that might be released to the public?

Hello!
I have been working with 3D modeling for about a year and a half now, and after working with Unreal Engine and making a few prototype games, I think I’m finally ready to make a game to try and release to the public!
before I get started though, I need a bunch of free textures (since I’m a little tight on money).
in recent models, I’ve used textures off the internet, but I know that I’ll probably have copyright issues if I use those for my games :frowning:
If anyone knows a web or place that I can get a bunch of free natural textures, I would be very grateful!
thanks!