Tiny Acquisitions - Tiny acquisitions is the only marketplace for internet business that are priced under $5,000.
Validated ideas - List of 5,000 poorly executed but popular apps
Microns - Microns.io is a marketplace to discover the best micro-startups for sale.
The 25 Days of Ideas - Free resources for coming up with startup ideas
MicroFounder - It's possible for a solo developer to build a profitable microstartup to pay the bills and live life on their own terms.
IdeasAI - OpenAI-powered startup idea generator