Moddb was mentioned. Another good one is thunderstore. It all depends on the game though. Valheim (and several other units based games) is very active on both Nexus and thunderstore, stalker games tend to be moddb, &c. Nexus tends to be the main one for most games though.
I mostly like Nexus (paid member), but I share the concern about it being the only game in town for most games. Nexus is heaps better as a site than both moddb and thunderstore ime, but the lack of real alternatives is putting way too many eggs in the same basket.
On the one hand that’s supposedly to do with competitive advantage. It makes sense to try to even the playing field, which should have nothing to do with objection on ‘moral’grounds. I’d argue this is mostly a good thing given the iffiness of many groups’ morals.
Case in point, your exact examples, which brings me to the other hand. Banning trans athletes on ‘fairness’ grounds is bullshit. In most sports there’s no known competitive advantage. Where there’s an imbalance they tend to show disadvantage. The rare cases with an advantage for trans athletes tend to disappear the moment you correct for size/weight, which is not something we’d exclude cis athletes for. None of your examples should have happened. They do not hold water on fairness grounds, and any moralistic reasons behind it are reprehensible.