Jacen1008:
Does anyone have a specific thing they added to their diet that they think really helped them gain
when i started gaining, i think my periods of big gains were related more to behaviour than a particular food.
my initial gains were fueled by alcohol - going out, drinking a bunch, eating a bunch... then coming home and having another dinner, etc. hangovers are a great motivator to eat more greasy, starchy food, too, i think!

the other habit that made me gain was repeated stuffings: pushing my limits by being fully stuffed, and eating beyond that. if you maintain that for a little while (days and weeks) i think you will find that your actual stomach (the internal organ itself) gets stretched, which leads to two changes: first, you can eat more in one sitting (increased capacity), and second, you will find you get hungrier faster between meals.
my biggest gaining year was in 2020. i lived alone for most of the year, i was not a feedee, i had no feeder... but during the pandemic i was at home most of the time, working from home. and i found i was eating all of the time. all day long, sometimes just out of habit or boredom! that constant grazing and reduction in physical activity really caused me to balloon.
as far as what was i eating - everything! a lot of healthy food, too. i literally doubled my weight in just a few years, and i never drank cream straight, lol. the thing that really caused me to gain (without even wanting to) was that i developed a real love of food, i started to love eating for the first time. so that is a big thing - if you really like what you're eating, if you can't stop thinking about it, you're apt to eat more.