I believe Lane may be referring to meetup.com, which you could use to help organize and advertise the meetings but they do charge the organizer.  

You could put up small 8 x 11 paper signs like people do to advertise yard/garage sales.

I’ve been an agent for a few years now and have tried multiple advertising strategies such as ads on Facebook, instagram, and Google.

Most large cities in Texas are getting pretty rich now (probably just too advertised in the last decade as a "strong" state). 

Realtors like the signs in the yard because it is free advertising.

To further the conversation, how would someone go about advertising or finding buyers interested in that option?

Fair Housing Laws state that you are not allowed to discriminate (including targeted advertising) based on family status even if the house is more suited for families and families will love it. 

If the agent's then need to ask the agent to forward to the owner in the letter).3) Use a direct mailing campaign vendor to print out letters to send to my curated list.

I've seen that some people use this method as their ONLY form of advertising and it's become more successful as the months pass.

Under the real estate for sale section and contact the we buy homes advertising and tell them to add you to there buyers list and also look for any homes for sale that state they are the wholesaler and connect with them as well on Craigslist.