Q: Can I still use Mod Organizer for Oblivion? A: It's time to put on the big boy pants and leave Mod Manager behind. It's best to read up on the beginners guide if you're not sure where to start. The Construction Set Wiki is a great source for all things related to Oblivion modding. Unofficial Oblivion Patch: I would consider this essential. The team creating these patches is highly reputable, and is currently working on unofficial patches for Skyrim. I am sure I read on my original installation that if I had SI, I only needed to patch with the SI version.
Click on the link to learn more on how to validate your archive. OFFICIAL ADD-ONS & UNOFFICIAL PATCHES: These mods I would consider essential. The Unofficial Official Mods Patch (2.7MB self-installer, 2.5MB OMOD install, or 2.5MB manual install 7-Zip file). In all this time I have been patching Oblivion with the v SI version. This issue can be fixed with just a few steps, but it's VERY important that you follow these steps or else none of your mods will work. There is also the matter of ArchiveInvalidation.
But just in case you don't want to go and deconstruct an OMOD archive to use with BAIN because it's too much trouble, then just keep Oblivion Mod Manager handy. However you can use a little tool that comes with Wrye Bash called BAIN to install other archive files such as 7z, RAR, and ZIP. Most of these files have not been looked at in years, but they should still work since the Oblivion community is more or less in a stable state these days. Now you don't have to use OMODs all the time, some mods aren't packed in as an OMOD file and are just structured as one, saying that it's ready to be installed as an OMOD. The Open Cities Patch Collection for Oblivion This is a collection of various patches made to provide compatibility between Open Cities (Classic or Reborn) and other mods. It's fairly easy to install, just click on it and it will promt you to a some options that you can choose depending on your personal preference.
What's an OMOD? An OMOD is an archive that's specifically made for Oblivion Mod Manager.