Ask HN: What will help me come up with startup/app ideas?

I really love web development, and I finally have enough skills (at Node/React full-stack webdev) and free time to build anything I want, and there's nothing I want more than to make something cool and useful. But I have absolutely no good ideas, I've been stuck for a long time, and I can't figure out why.

I've read PG's essays, watched startup school videos, read countless books on startups and project management and creativity, and I still fail to invent something new/original/useful.

Any tips or advice would be very helpful!

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I have also have already built a bunch of projects (you can check them out at https://rayalez.com), they have some traffic/users, but I ended up getting stuck and I have trouble finding a way to take them further than initial few hundred users. Which one of them do you think looks the most promising? What can I do to make it more successful and turn it into a business? What would you do in my place?