What you are describing is the overarching category of "shooting bags".
A game changer is a specific type of bag, now made by Armageddon gear. The Wiebad fortune cookie, warhorse development saracen, etc are very similar. These "wrap" around the edges of a barricade wall, creating a lot of stability. There's slight variations in the various models, size and weight being the bigger differences. Bigger and heavier generally equals more stability, but it's also more weight and a bigger footprint to pack around. I prefer the smaller sizes myself. ~95% of the stability at 50% of the weight and size.
Beyond that there's rear bags, "pump pillows" and bags of all sizes and shapes. Square, rectangular, wedged shape, cylindrical, small as a sock to as big as a VW beetle.
Personally, I just use a Wiebad mini fortune cookie and a precision underground rear bag, it covers 95+% of anything I'll encounter at a match. Both very versatile.
Don't overthink bags, keep it simple. My personal recommendation is a barricade type bag of your choice (game changer, fortune cookie, etc.) and a rear bag of your choice. Get proficient with those two bag styles and you won't need anything else.