Tes4Mod:Popular Outdated Mods

Either upgrade to a working alternative or get rid of them. All of the mods listed below have working alternatives; or, in some cases, working updates.

Mods with Serious Bugs
Please, do not use these...

'''Hrmmn's Oblivion Script Optimizer - offers negligible FPS increase, at best, and some script changes are buggy: There are many alternatives that target this area.
Martigen's Monster Mod pre-version 3.5.5: See the MMM thread at the BethSoft forums for the latest version.
Oblivion PolyGone Overhaul - "has several serious issues, the most critical of which is the meshes for rocks all had their tangent space data stripped which is extremely likely to cause the game to CTD. Freezing might well be caused by this." ~Arthmoor
OBGE.dll, the version packed with Screen Effects - causes a crash on interior-exterior transition bug
OBGE DLL v01 Debugged (still buggy): OBGEv2 is available with the Oblivion Graphics Extender Project 
:Note: You can just download the OBGEv2 DLL and rmove "OBGE.DLL". The other files are not necessary if you only use ScreenEffects.

Outdated Mods
Old (bugged) version: Fix (or Alternative)
Bedrolls (outdated): aaaBorsBedrolls v1.4
If you want "real" sleep and portable bedrolls: Real Sleep Extended
Book Placement v1: Book Placement v2
  Use the ESM OR the ESP, not both.
Combat FPS Optimizer''': Combat FPS Optimizer Updated
This mod is superceded by Streamline, which offers much more functionality with its StreamSmooth feature, alone.
If you use the updated version, disable Streamline's StreamSight feature.
This mod is compatible with OSR.
Darker Dungeons:Let There Be Darkness
Let There Be More Darkness offers compatibility for a number of mods, a good companion to Let There Be Darkness.
Cava Obscura, instead of setting everything to 0, tries to keep some of the authors' intentions in mind and sets lighting to 10% of the original.
You may still wish to install some component of Let There Be More Darkness, as Cava Obscura's mod compatibility does not cover one or a few of the mods that the former does, but, overall, Cava Obscura offers coverage for more mods.
Darker Nights:If you use a newer weather mod (i.e., AWS, All Natural or Enhanced Weather) turn on Darker Nights via your weather mod's INI settings or using your weather mod's Darker Nights plugin. 
Harvest Flora pre v3.0.1: Harvest Flora v3.0.1
Version v3.0.0, the version bundled with OOO 1.33, contains a serious bug that can cause crashes in Oblivion realms.
The v3.0.1 plugin's version number was not changed; it still reads "3.0.0". This is also the value read by Bash in the File view.
Illumination Within and Relatives (not optimized enough): Animated Window Lighting System
Additionally, if you really wanted the "see outside" part: All Natural
Living Economy (a bug or two): Enhanced Economy
EE is not subject to LE's 65k bug.
EE minimizes the chance of price changes being saved to the save file, avoiding the bug plaguing users who try to uninstall LE and find that its price changes remain.
LE's mercantile leveling feature is also broken.
EE is more compatible than LE, particularly in three notable cases:
 
Map Marker Mods (nearly all are made obsolete by MMO): Map Marker Overhaul
Natural Environments - Natural Weather (buggy): RD Natural Weather Unofficial Test Fix
Another alternative in which to find the NW weather: All Natural
Natural Environments - Natural Vegetation (not optimized): Enhanced Vegetation
Natural Interiors (unfinished): All Natural
Quest Award Leveling (outdated) and Quest Award Leveller by Quazzy (buggy): Quest Award Leveller - Now Supports Battlehorn Castle
Alternatively, if you really only want to receive the best version of leveled quest awards you can try DB's Static Quest Rewards.
Real Lights (unoptimized, buggy, bad edits, save game bloat): All Natural 
:Note: It is possible to only use the Real Lights component and not the whole weather mod. (See the AN ReadMe for instructions.))
Streamline <3.1b (any version other than 3.1b PATCHED after installing 3.1b!! is old): Streamline download@TESNexus
Any version of Crowded Roads older than "revisited variant": Crowded Roads Revisited


See Also
Stabilization and Optimization Mods
Stabilization and Optimization