Let's see. The first big one I got was a 28" meteorologic so called pilot balloon designed to take angle reflectors quickly up to higher altitudes. They were durable, incredibly hard to inflate and when popped - like a gunshot. I liked them but they were too tough to play with.
The first big, better to say long one I bought was a catepillar balloon, at least 48" fully inflated.
The first big round ones I received from Mike D. - yes, he shipped me a bag of the famous "Mellyloon 16-18" Uniques. I loved them, the twist in the story that I love B2P but they were too nice to waste

Soon after that I visited Canada and managed to buy many big balloons: Tilly, Tilco and also some Qualatex 24. The biggest I received from a friend was a 72" round French tricolor balloon and need to mention the Olympic 45" that I bought regularly when worked in Kyiv

Finally, how I used them? Let me say that I told to a cute woman when she discovered my colorful balloon room and asked why they were there: "Just use your fantasy!"