I've been running a little RPG meetup group for last two years, and it's been going quite well. We've been using Discord and Meetup to schedule events, and the group is growing.

One thing I'd like to do for the group is set something up where GMs could propose games, both one-shots and campaigns, that they'd like to run. Some kind of online site where GMs could explain what they wanted to run, perhaps adding a few links about the game, and what days they'd be available to run something. Also, players could respond with their availability. Perhaps a polling system to see what games have the most interest. This would just be for face-to-face games in our local group.

Neither Discord or Meetup really work for this. Discord messages fade away too quickly and Meetup events are fixed to a particular date and time.

I was thinking of perhaps cobbling together something using Wordpress, but I thought I'd ask around first.

Has anyone done something like this before? Is there a web service already set up for something like this?

It's the thing where local forum win

-can be read by non member

-are local focused

-Easy to run/manage

A pitty that they have been replaced by meet up/Facebook ( and their fcdi alternative)

I don't know of a platform that specifically caters for this. Would be interested to see what others suggest. I've found opportunities locally at game stores, Discord, through meetup, and also through Reddit (apologies Lemmy but there is not enough user base for a city based ttrpg comm here).

Meetups is good if you run a regular session and are open to drop ins
Discord and Reddit or some forum styled website would be better to fish for interest in something, but people's schedules and priorities change so you will have to ask regularly. Not much you can do about this. I don't see this as the platform's fault, rather the nature of what you are trying to coordinate.

If discord messages fading too quickly is an issue you can create channels for the different games you are trying to run, or give each GM their own channel for whatever they're pitching, and pin a message in each so they don't get buried into oblivion. I have joined servers that use this system, not for ttrpg admittedly, but this functionality solves that issue.

You can use Google Forms to get the RSVP functionality you're looking for. And maybe a dedicated Discord channel with suitable posting restrictions so it's JUST DMs posting such forms? Or you could even have them DM you their pitches and you post them, such that you can make the channel so only you can post. I also like using this tool for scheduling: https://www.when2meet.com/

I don't run games but I would use https://lettucemeet.com/ to poll availability depending on system and one-shot or campaign.

Fall back on discord for communication once you have a group to hammer out location and finer details.

Sounds similar to running a West Marches style games. Pool of GMs and Players.

Could Mobilizon be used for that?

EDIT: for finding a date for some other thing I've been happy with how Polls in Nextcloud work. But NC might be too big for your needs. Maybe something from those would fit you?
https://github.com/manfredsteger/polly
https://awesome-selfhosted.net/tags/polls-and-events.html

Warhorn?