I think it's snappa.com that I came up on last night when I was making some research on how to tune up my design work and I checked it out. It was so sleek that I'm beginning to fall for it especially in designing banners. It's almost like canva but a little bit different.There's alot of site out there to learn graphic design. Coursera I think is the best, have been leveraging it for over a year now. I really benefit from it, added new skills to my existing skill with Coursera. You can go make research about it, before joining.