Suggestions for idea space

Looking to start a startup with couple of friends. One i know from graduation and one from post graduation. 2 of us including me are in the software dev industry for last 11 years with 6+ years in ML/AI. And the other one is into business development and skilled at bringing in clients from india, Middle East etc for B2B domain. We all have worked across a variety of domains and industries. Have been watching YC school playlist and one of the things mentioned in how to get a startup idea is finding a good idea space. Some examples mentioned in the video are software for trucking industry, fintech for real estate etc. Would appreciate if anyone can suggest similar idea spaces that could be a starting point to explore ideas within that space and then evaluate multiple and narrow down to one.