Don’t think they had those in Aus. Looked them up as I thought they were a packet I used to occasionally get from this amazing school shop that had every lolly(sweet/candy) imaginable. Walking in there was like entering WonkaLand! lol These rectangular packages were filled with things like a collectible funny “Confucious Says ...” card, bubble gum, a lady finger with a red painted nail, stickers, that kind of thing.
Wacky Packages look like what Marks & Spencer(the grocery store over here) brought out pre covid. They brought out what they sell in miniature collectible form eg their famous percy pigs, a miniature M&S OJ etc. They even brought out mini M & S shopping trolleys to place the items in. I have a small collection.
Collecting stickers as a child used to be popular. I still have my collection with MASH stickers, Aussie Radio Station Stickers ... Humphrey Bear lol No Romper Room ones though! 