[Samsung Galaxy S Duos] cheatman:
List of compatible Themes:

Flash the themes by rebooting in recovery mode and using CWM to install ZIP. It's a good idea to clear caches and dalvik before testing them out:

Greenblast Theme by charles111 - Get it here: https://www.dropbox.com/s/2dm0w4hc69jyyfd/the greenblast v2.00.zip (theme thread here)

PurpleGlow Theme by Mohitash - Get it here: http://xdaforums.com/showthread.php?p=42058670

BlueGlow Theme by Mohitash - Get it here: http://xdaforums.com/showthread.php?p=42093164

CyanGloss Theme by Mohitash - Get it here: http://xdaforums.com/showthread.php?p=42170668

BlueGloss Theme by Mohitash - Get it here: http://xdaforums.com/showthread.php?p=42194443

List of compatible Add-Ons:

These add-ons provide additional functionality to the ROM and do not bork already existing features. None of them are mandatory and you can install only the ones you want. To remove an add-on that was flashed using CWM, simply reinstall the KyleOPEN ROM again and the add-ons you want to keep. There is no other way to uninstall a CWM package with ease.

Remove menu-to-kill feature - Flash using CWM. This will disable the feature to kill running apps by holding the menu button.

FaceUnlock - Flash with CWM. Will enable face unlock in security settings after boot.

CM9 Gallery - Flash with CWM. Installs the CM9 gallery and video player.

CM9 Apollo Media Player - Flash with CWM. Installs the CM9 media player Apollo.

Stock Gallery - Flash with CWM. Installs the stock Samsung Gallery (allows you to change wallpapers and everything)

Stock Keyboard - Flash with CWM. For those of you that miss the stock Samsung keyboard.

Stock Launcher (TW) - Flash with CWM. Installs the stock launcher and hogs the phone again. Also for the nostalgic types.

MIUI Camera - Flash with CWM. Replaces stock Samsung camera to fix recent photo bug. Does not support 5MP mode and cannot be configured to save photos to SD.

Swap SD cards - Flash with CWM. Switches the internal memory and external microSD cards between them to allow downloading of HD games and apps that need lots of space on the internal SD. BEWARE: Doing this will automatically make the kernel go haywire and battery impact is considerable. You will not see the errors (apps run fine), but the phone will enter sleep mode very rarely due to the checks it does constantly. However, it is completely safe and no functionality is lost (thanks to hybridmd for the init.d script!)

Samsung S Voice - Copy to device and flash using CWM zip installation. Original work and hacks by Wanam for SGS2.

Stock Samsung Theme v1 - Flash using CWM to revert to how the phone UI looks while stock.

Blue ICS Theme v1 - Flash using CWM. Changes the touch sounds from the annoying bubbles to CM9 sounds, changes boot animation to Nexus 7 one, changes UI to blue theme and remake of SIM icons (not in settings yet). Screens attached. This is the default since v2.x of the ROM so there will be no change if you flash it.

All removed APKs - Flash with CWM. This 120MB package includes all removed APKs from the stock ROM. Flashing this will undo my work in 30 seconds, making your phone near stock, but deodexed.

List of other compatible packages (not mine, not tested, don't ask about them):

XperiaZ walkman player with clearaudio+ and xloud, Note2 Gallery & Player from the Galaxy Grand Duos. Thanks dising007

CrossBreeder Lag reducer - Some users reported better performance with it installed. Thanks to idcrisis for posting it in the forums!

List of compatible kernels:

Please note: Regular users should stick with the kernel version included in the ROM by default. If you encounter issues with any of these other kernels, flash the ROM again using CWM to restore the default kernel.

GitHub link to the KyleOpen 4.0.4 Kernel: https://github.com/cheatman-xda/kyleopen-kernel

KyleOPEN Kernel v5 - Stock kernel with additional CPU governors, overclocking support, init.d script support, root enabled. Flash directly with ODIN. Credits go to VamshiStunner for his work on governors in this kernel version. NOTE: Although it seems to have OC, it is not working. Setting OC values will not boost the phone's performance as it will run at 1GHz no matter how you configure it.

KyleOpen ROM Kernel OC1 - Bleeding edge kernel with increased sensitivity, all features activated and custom boot logo image. Only for the hardcore fans and power-users of KOR that know what they're doing.

xvasek2 - Breakfast Kernels - OC Kernels for everyone, plenty of speeds to choose from. If you really want OC and can't get around with any setup, use these kernels confidently. Don't forget to follow the instructions and check your balls (or instincts for the ladies!) before you proceed. All kernels should be flashed using ODIN.