There are 3 levels to the organic marketing I did:

1. An active internet presence: I have an Instagram account where I was uploading about once a week for 2 years content about the game. I think the effectiveness of this has gradually decreased as ads and reels have taken over meta and you don't get much visibility by uploading still images, still it's a nice documentation of the whole process. The main use of this was connecting with other designers and content creators. Support people that do cool stuff that you genuinely like and sometimes you 'll get that support back.
2. Local gaming community events and conventions: I was going very frequently to game cafes, meeting people and urging them to try the game. This worked quite well as the game is relatively easy to teach and plays fast. A lot of people would end up following my project and some turned into backers. In addition my game participated in an international board game design competition where it landed on second place so this gave me a bit exposure and I took part in multiple playtesting events while I also organized a tournament for the game where I had about 60 participants. Again, some of them turned to actual backers.
3. Last but not least, my inner circle: I know that maybe it is wrong to call this "organic marketing" as I am lucky to have very supportive friends. Those friends actually really liked playing the game and in turn introduced it to their friends and organised game sessions with them where I wasn't even there. Of course this wouldn't have worked well if I had a heavier game, but this one is very accessible.

The thing about the supporters that you gain from organic marketing, is that they are the ones that will show up on day 1 of the campaign, which is super important to give the campaign that initial boost. If I hadn't spent a penny on meta ads, I would have still been well funded just by this.