Java Edition:Ice (Item)
Ice as an item wasn't supposed to be available until 12w17a (1.3 snapshot) but was obtainable three times before this.
Obtaining
Beta 1.6 Test Build 3 Debug Chests
In Beta 1.6 Test Build 3, any newly generated world would contain up to 11 debug chests with every item in the game. The ice item was obtainable in the chests 3rd and 7th from the left in the 21st and 5th slots respectively, in stacks of 64.
Silk Touch
When Silk Touch was first introduced in Beta 1.9 Prerelease 4, it could be used to mine many blocks that weren't supposed to be obtained. These included spawners, lit furnaces, and stone monster eggs. Ice could also be collected in this version. In Beta 1.9 Prerelease 5 they changed ice to not be collectible via Silk Touch due to the exploit allowing water in the Nether. Once this bug was fixed they readded Silk Touch's ability to get ice in 12w17a (1.3 snapshot). The player can find the ice to mine in cold biomes and expose water to the sky to let it freeze in these biomes too. Note: a pickaxe with both Fortune and Silk Touch will also work to collect ice.
B Creative
In the version 11w49a (1.1 Snapshot), pressing B would toggle the player between Survival and Creative mode. This allowed the player to access the Creative Inventory where the player could then grab {item}.