I actually started building something like this too, I think it's a pretty common project idea. I ended up finding raindrop.io which I really really like. Maybe you can check it out. The free version is good enough for me at the moment but I'm considering upgrading. I use Pocket to save stuff I'm gonna read later, then if it's a really good resource I put it in Raindrop and categorise + tag it. It also has moodboard if you wanna save images as references.