Doesn't really matter if it is free or not. Finding somebody's patreon is another thing that the listing catalogue makes easier. I don't think forcing people to sign up for discord is better than a webpage people can view and search easily. I might add a listing harverster for discord in the future if it makes sense. AI Mod Catalogue is supposed to eventually be the functionality of the steam game search with an easily decentralized database akin to torrent trackers. In fact I'm adding user defined tagging and filtering beyond the core categories next. If somebody wants to find high heel shoes then using something like the steam game search page is going to be a lot easier than looking at a forum or discord. Regardless, free or not has nothing to do with it.
Since you're about four years out of date, I'll catch you up to speed.
The spaghetti tangle and attribution mess that was HongFire is dead. Doornail dead and never coming back, nor is anyone likely to want it to seeing as people like flashbangzzz were able to get threads stickied on hongfire with stolen content, most especially modders likely aren't going to be all ears on any kind of resurrection. Hongfire was a trainwreck of broken pages broken authors and broken links. Ain't nobody got time for that.
The last Illusion game that sold well over budget and expectations was Honey Select. The launches since then have been squarely in niche territory for pretty obvious reasons. Since these games sold and played super niche, the modding community moved squarely in that direction. Which means, flatly speaking in a factual manner, the modding moved to
Discord. Period. AI Girl modding lives and dies on Discord, period. If you meander back over to the topic you started posting in, you'll note that most of the mods listed are Patreon and
public re-releases of mods based entirely in Discord.
Free or not has a great deal to do with it because of the games' until now launch and curation history. Quite frankly if it wasn't for STN being the hentai batman both needed and deserved, and AI girl selling about three times more copies than they thought they were, with a western release possibly imminent, this likely would be a different conversation. One part however about that conversation unlikely to change is Discord is where the modding is. That's the way modders want it, and the users thereof seem fine with that situation, so you might want to pull back from that really pretty tree you're staring at so you can take a look at all the other trees behind it, cause the context matters pretty significantly.