The first mention of a bot that used item trading as a mechanic was on April 9th, 2021 in a direct message with one of the former developers

This was the first message that started the creation of the Unbox.tf bot, then known by the name 'TF2 Virtual Trading'.

The technically first unbox was done in a private discord server. At this point, the bot didn't even have a database. Very epic item.

It would be easy to confuse item number 1 (the Antarctic Parka) as the first ever unbox. But this is not the case, and will be explained further down. This is actually the first ever unbox stored on the item server. Unfortunately, this item has been lost to time, and its existence in the current item server is unknown.

The first ever item unbox was hand-picked and was not selected from a drop pool. Shortly after that item was created, the first proper drop pool was created by copy and pasting from the TF2 Wikipedia.

Trading was always supposed to be an important part of the bot, this was the first iteration of a trading interface. The Ghostly Gibus shown may be the same one as the first unboxed item.

This was the first unusual item unboxed.

As a result of copying and pasting from the TF2 Wiki, the first ever bugged item was created as a result of an invisible character being added to the end of the item. This lead to the creation of the Vintage quality, given to items that were created by mistake or have a mistake in them.

Before unboxing used GIFs, there was a countdown from 5 that was used. This turned out to be much more resource intensive than a GIF, so we switched to these.

Pretty self explanatory