Thanks for this thread. I was looking for something like this a while back, and it seems there's now not one, but several options.
I've checked out both RAWG and IGDB (as they seem like the ones with the most features and active development - I love seeing devs actually interacting with the community), and they both seem pretty good.
For RAWG, I like how it shows game info, particularly the creators section. Although the super bright green "Rate the all time best games" banner does kind of ruin the overall look. And the recommendations features that are supposed to be in the works according to this thread seem like they could be great.
On the other hand, the overall database is pretty lacking compared to IGDB (at least for PC games), and also sometimes wrong (For example,
Magic: The Gathering seems to have merged the old Microprose game and the Xbox version together, so you get the description and box art of the old one, achievements and store info of the new one, and screenshots of both). Some of these seems like they could be fixed through the edit game UI (although I'm not sure what the policy there is for new users), but the achievements thing doesn't seem like it's editable, and neither is the creators section. The list of genres is also very limited IMO, as it's missing things like interactive fiction/VN or rhythm games. I'm also not a huge fan of the rating system, as it seems too limiting, but I can live with it.
On the other hand, IGDB has a more complete database in terms of games I care about, but with much more limited info on them (the more obscure releases mostly just seems copied from the Giantbomb database). And the overall interface seems to have slightly less features (I like how RAWG let's you mark games as completes/abandoned/... without having to make separate lists). I do however prefer the cleaner design of the site, as well as the normal rating system. I also like that it has the option to export the list to a csv file, which seems useful in case the site ever goes under or something better just comes along, as it can ease the process of migrating somewhere else. It's probably something no dev ever wants to plan for (why make it easier for your users to abandon your site right?), but after my experiences with myanimelist, it's a feature I very much appreciate.
I'm not really a fan of how either of them display collections/lists though. I'd prefer something simple like myanimelist or anilist has, where you just get a clean, sortable list of all games with their ratings, but neither of the two seems to do that. Still, It's nice we finally have sites that let you categorize games with a somewhat complete database, so I'll probably stick with one of the two, as I've always wanted to get a list together just to see how much stuff I've played throughout the years.