How does one goes about startup mentoring? I will not promote

Through my corporate job I had a chance to work as a startup mentor for a year - no pay or benefits, but I thoroughly enjoyed it. Now our company shut down startup accelerator we had so that’s gone… I cannot help myself but want to keep doing it - in all honesty it has been the most appealing part of the job I had in the last 12 months, something i would love to do the on the side. I was thinking of writing to other accelerators but couldn’t really find any info on their websites when it comes to mentorship. And most certainly I don’t want to be a weirdo messaging founders on LinkedIn out of the blue. How does one go about it? Not for money, equity or benefits, but because one just enjoys it and finds meaning that the corporate world cannot offer? I will not promote