Made for Omnifactory 1.2.2. Don't try to apply it to later or earlier versions!
This guide covers the installation of most unofficial fixes for the 1.2.2 version of Omnifactory. Mainly, these are the custom jars by Exa that would have been included in the pack proper if Curseforge allowed it.
This guides assumes you already have 1.2.2 Omnifactory installed. Link, select topmost(latest) file.
Originally a zip of fixes for 1.2.1, most of it has been integrated into the pack, except for the GTCE and Shadows of Greg jars (push the Download button). They are backports of GTCE/SoG fixes on Omni's version of GTCE. No, you don't need the rest of the Exa's fixes (scripts, etc) - they are integrated into 1.2.2, only the jars aren't. To install, just replace with them the similarly-named gregtech and Shadows_of_Greg jars in the mods folder of your instance.
Links to the repos for Exa's forks, to be compliant with *GPL licenses: GTCE, SoG. You probably don't need these links - use the ones in the previous paragraph.
This section is for the really unofficial stuff, made by fans of Omnifactory for fans of Omnifactory.
A relatively minor change in AE2 logic, optimizing it to not recalculate the entire network if anything changes when AE2 is in channelless mode. The PR for it to be included into AE2 proper was rejected, but there have yet to be any known problems from using it. Advantage: massive improvement in recalculation times for big channelless AE2 networks. This doesn't affect lag from working, only the freezes when you change something in the network's structure.
All the builds of Talchas's fixes are on the repo, but for 1.2.2 specifically you want the rv6-stable-7 build, not the rv6-stable-6 one - they are for different AE2 versions, since in 1.2.2 AE2 was updated to stable-7. Here's a direct link to the release you need for 1.2.2. Replace your AE2 jar with it, just like with Exa's GTCE and SoG jars. Bonus: see how there are two jars in each release? If you're a server owner, you can download the jar that is named the same as the normal AE2 jar, and if you replace AE2 with it on your server, you won't need to make all your players install the fix to be able to connect - it's serverside-only.