Over the years Minecraft has had many different editions. The original was Java Edition, the current largest is Bedrock Edition, and there are also spin-off games like Minecraft Dungeons.
Java Edition was publicly released on May 17th, 2009, running on the Java codebase. It is still supported to this day, with much of Minecraft's technical, redstone, modding and PVP communities using it due to its mechanics. It is available on Windows, Mac, and Linux. During update cycles, there are (usually) "snapshots", typically released every Wednesday, which add some features planned for the next major update. Snapshots are typically more consistent and and have more features than their Bedrock Edition equivalents.
Bedrock Edition was formed with the combination of several older editions: Pocket Edition, which was the largest, for Android, iOS, Kindle Fire, and Windows 10 Mobile (formerly on Samsung devices as well); Windows 10 Edition (originally a Universal Windows Platform port of Pocket Edition); Gear VR Edition, and Fire TV Edition. This merge happened on September 20th, 2017. Minecraft was available for Apple TV for a short time but crossplay with the other versions was not possible, and after a bug was found preventing it from updating, it was discontinued. Bedrock Edition is also available on Xbox One, PlayStation 4 and Nintendo Switch, which all originally each had their own Legacy Console editions, but these were discontinued when Bedrock Edition became available on these platforms. It can also be played on the Xbox Series X|S and PlayStation 5 respectively via backwards compatibility. Unlike the versions mentioned previously, the Legacy Console versions could not be directly merged into Bedrock Edition, they had to be installed separately, though things such as worlds and skin packs were able to be transferred over. Bedrock Edition became available on Xbox One on the day of the merger, it released for Nintendo Switch on June 21st, 2018, and for PlayStation 4 on December 9th, 2019. Bedrock Edition was discontinued on some older models of the platforms it was available on, mostly with mobile devices, and entirely for Gear VR and Windows 10 Mobile on October 31st, 2020. As mentioned previously, Bedrock Edition has "betas" which are similar to Java snapshots, but are only available on Windows 10, Xbox, and Android.
Legacy Console Edition (the "legacy" being added to reduce confusion between the original versions and Bedrock Edition on consoles) were several version of Minecraft for different consoles, developed by 4J Studios. The Xbox 360, Xbox One, PlayStation 3, PlayStation 4, PlayStation Vita, Wii U and Nintendo Switch each got their own. Multiplayer was only possible between the same console types, though some versions allowed things such as world transferring between each other (eg; Xbox 360 to Xbox One or PlayStation 3 to PlayStation 4). As mentioned previously, Xbox One, PlayStation 4 and the Nintendo Switch discontinued their LCEs for Bedrock Edition. The older consoles continued to receive updates until 2018 with Update Aquatic, due to less than 5% of active Minecraft players using all of them. However, Minecraft continued updating the games on these platforms much longer than other games did on the older consoles. Via backwards compatibility, Xbox One Edition and PlayStation 4 Edition can be played on the Xbox Series X|S and PlayStation 5, respectively, same as Bedrock Edition.
There are also several miscellaneous editions: Minecraft was available on the New Nintendo 3DS from September 2017 to January 2019, with it being discontinued at the latter date. It was developed alongside Other Ocean Interactive. There was also Minecraft 4K, a version of Minecraft taking only four kilobytes of space, as well as Minecraft Pi Edition, a version for the Raspberry Pi microcomputer, but neither were intended to be anything significant and were almost immediately discontinued. Education Edition is an extension of Bedrock Edition intended for educational purposes, and is available on Windows, Mac, iOS, and despite Bedrock Edition not being on it, Google Chromebook. Due to the Chinese Communist Party's policy of heavy internet censorship in China, a separate version of Minecraft was made for mainland China (not in Hong Kong or Taiwan). It is free but can only be downloaded in China and, like Education Edition, receives updates slower than the Java and Bedrock Editions.
Finally, Minecraft has a few spin-off games. Minecraft: Story Mode, and its sequel, Minecraft: Story Mode - Season Two, developed by Telltale Games, were choose-your-path story games, released episodically throughout 2015 and 2017 respectively, across different platforms, with both being discontinued when Telltale Games went bankrupt in 2019. Minecraft Earth was an augmented reality game released for mobile devices in October 2019 but its gameplay, intended to be outside, was severely restricted by the COVID-19 pandemic, and it was discontinued in June 31st, 2021. Minecraft Dungeons is an action RPG dungeon crawler released on May 26th, 2020, with several DLCs being released for it and more in development.