If you scroll down the home page, you'll come upon a set of links to various Richmond-related groups. From there, you may find what you're looking for.
I have a lot of clients who are homeowners in the Richmond, so if you come up dry, let me know & I'll ask them if they know of any groups. They also have children and would probably know of related associations.
There is the Richmond Community Association. Tehy are part of the Coalition of San Francisco Neighborhoods and very active in planning issues. In fact the lead contact person, Hiroshi Fukuda, is the chair of the CSFN planning committee.
They claim the boundries of Arguello to the beach and Lake to Fulton. If you go east of Arguello then it's Jordan Park Neighborhood Association.
There was or is a Richmond Neighborhood Coalition and a Planning Association for the Richmond that Ron Miguel, the current president of the Planning Commission has been active in.
If you want more you know where to find me.
It is always good to feel like you are part of the community that you are moving to. When my children were younger and we moved to D.C, I didn't know anyone in the neighborhood yet. I learned about an organization called m.o.p.s. (It stands for mothers of preschoolers.) I don't know if this would apply to you or not but it really helped me to get to know other families that lived in my area and it was great to have play dates with friends who had similiar aged children and interests. Most likely churches in your community or recreation centers nearby could give you information about it or you could even go online and find the closest group to you. Another idea would be to ask neighbors if there is a civic league within the community as that is what we have here in Virginia Beach. They post the times and locations for the meetings centrally in the neighborhood so everyone knows ahead of time. As my children have grown and we relocated to the oceanfront, I realized I missed having time set aside for friends without the kids sometimes. So I started a group called Bunco. It consists of twelve girls that live local to me with similiar goals and interests. It is once a month and each girl takes a turn hosting it once a year. The hostess picks the theme for the evening and provides the refreshments. (Bunko is a dice game that we play but it is really more about the girl time than anything else.) As a last resort ask the neighborhood mailman you would be surprised how much information they know about!
I have a VERY old neighborhood organizations directory, but it may point you in the direction to find more info. There may still be a Neighborhood Organizations Secretary in the SF Planning Department. The number (which may no longer be good) is 558-6392. You might also try sfgov.org and do a search.
As for the groups themselves, you may want to try calling the office of the district supervisor.
Also a group called CSFN (Coalition for San Francisco Neighborhoods) is bound to know. You can do a search for them on line.
I also see the Richmond Community Association, Richmond District Council, and the Richmond Environmental Action.
Hope that points you in a direction. Good luck.