These are ones I use a lot at the moment for the stuff I make...
Chat GPT - All sorts of creative assistance
Chat GPT is coming on leaps and bounds. It's free, quick and easy to sign up and use. No copyright issues for the stuff it creates. Great for asking it questions and getting quick answers (although you may need to fact check it once in a while to make sure it's right in the details as it does make mistakes sometimes).You can also ask it to make you an image. It might take a few tries to get it right but if you're specific and bossy enough it usually gets there in the end. But you only get a certain number of tries at once on the free version.
Click on 'Explore GPTs' for other things the AI can do for you. There's a slide maker that will give you a Powerpoint file to download. But if you're good at making nice looking slides, you may be disappointed. But still worth a play!
Unsplash.com - Copyright free images
FREE, quick and easy to sign up and use and you can search for tons of copyright free images. They're usually beautiful too! Just m,ake sure ytou filter the searches so you only get the free to use ones if that's what you're after. But there's loads!
Pexels - Copyright free clips for videos
Again very quick, easy and free to sign up and search for clips you want to drag into your video edits. All copyright free and can be uploaded to Youtube etc no probs. I was super excited when I realised this stuff exists for free now. You can pay lots for better ones but these are all pretty great!
Perchance - AI images
This is the one I landed on because it's free, quick and easy to use. It has lots of style options to explore too. I use it a lot to make cutaways for videos or images for slideshows. All images created are royalty free of course. They're fairly high resolution but perhaps not as high as you might like so try searching for a free 'image upscaler' website. I would put a link here but the one I've been using isn't working at the moment (grrr). Hold on... this one's pretty good.