Canva
When Canva first came out, as a professional graphic designer, I immediately judged it to be strictly for amateurs or beginners. Oh boy, was I ever wrong. Canva has evolved into one of my favorite go-to graphic resources, even over Adobe Photoshop for certain things.
Their free stock photography files (and video and vector) are helpful, when you need a quick image, and even their image AI works well and is improving all the time.
I also appreciate the new design features and tools Canva adds on a regular basis, without having download anything. I can also share files with my clients, and easily download in a variety of formats.