Fill Me Up is probably the best VN/Ren’py game that’s still in development (in my opinion). Other than that, you’re probably best off looking in the “ren’py” category - there are plenty of life sim-esque VNs there. I don’t personally enjoy that type of game much, but there are plenty of options to choose from if that’s your thing.
If you’re looking for VNs that are no longer being developed, there are some good ones out there as well. Growth Academy is a pretty fun one with lots of content (just looked and it seems like this is still being developed, my mistake); just make sure you romance the chubby girl to get to the weight gain content.
If you don’t mind furry stuff, then Waist of Space and Expanding Horizons/The Interview I and II are great. There are 4 total games, and there’s plenty of content throughout. Fair warning, though - if you decide to check these out then I recommend starting with Waist of Space, since the others aren’t so explicitly focused on weight gain. Expanding Horizons focuses mostly on inflation, and the WG content in Interview I/II is fairly well hidden. If you enjoy Waist of Space and want more, then I’d recommend checking out the other games.