iSponsorBlock
A jailbreak tweak that implements the SponsorBlock API to skip sponsorships in youtube vidoes.
More info about SponsorBlock and the API used can be found here.
This tweak has been tested on the latest YouTube version (16.18.5) and supports, at least, down to version 15.31.3.
Installation
Add the following repository: https://galacticdev.me
Customization
To access this tweaks settings open the YouTube app, and there should be a button in the top right, like in this image: https://imgur.com/lLpfXue.