they are all tested, but i admit they are still far from great, still, i would appreciate if you guys would want to give them a try:
Chubby Dog Girlfriend:https://c.ai/c/Mtk6eKf31x_Hem0M92NcxxVAXQcD5EBC8gjLjpz4Jk4
Fat Splatoon RPG: https://c.ai/c/-g5g3GshfF3jLCdx0MPDZjtDHNH70v9E4_o7Njq9NBs
Obese Octoling Boy:https://c.ai/c/LNNChQgZIZHDLX6HwjBpufHIsg9Uo30WAcTJGe-e920
there are other public ai characters that arent really fat fetish related, however they can be used in that way