Electra

Electra is a semi-untethered jailbreak for all devices running 11.0 - 11.4.1. There are two versions of Electra - one supporting iOS 11.0 - 11.1.2, and the other supporting iOS 11.2 - 11.4.1 and tvOS 11.0 - 11.4.1.

Electra for iOS 11.0 - 11.1.2
The first beta for iOS 11.0 - 11.1.2 was released on 2018. Several betas were released. The betas did not include support for Cydia, however the developer, CoolStar later seeded six release candidate versions to developers with working Cydia support. Electra1112 was then officially released on 2018.

Electra for iOS 11.2 - 11.4.1 (tvOS 11.0 - 11.4.1)
With Electra's update to support devices running any iOS between 11.2 to 11.4.1, delays came in place due to Apple's APFS snapshot mitigation of remounting the root filesystem as read/write that was introduced in iOS 11.3. There are many parts of a jailbreak that need read/write to do certain things within the filesystem, and because of Apple's mitigation, a APFS remount workaround was needed to complete the jailbreak. Chinese security researcher Min Zheng had already found and created his own bypass to remount the root filesystem, which many other developers then tried implementing in their own way. During this time, Jonathan Levin, creator of the LiberTV jailbreak for the AppleTV was announcing his plans for updating LiberTV with an APFS remount which the Electra Team could use. Meanwhile, CoolStar had already found a 0day in APFS which would allow the filesystem to be remounted as r/w, but wanted to save it for future use in iOS 12. As this news was absorbed by the community, many people were angry that CoolStar wanted to delay the update for Electra by saving the 0day. However, CoolStar had found yet another 0day and decided to end the waiting on Levin's remount and use one of his APFS 0days instead. Electra1131 was then released a little while later on 2018.

Support for tvOS 11.2-11.3 was released in a separate IPA on 2018. Nicknamed "electraTV", this was released in conjunction with nitoTV, who has also released jailbreaks like backr00m, and Jaywalker.

Support for iOS 11.4-11.4.1 was added on 2019.