Unreal Tournament 2004 mutators made by me:
InstaGib 4Ever (version 1.05) (screenshots)
Selecting this mutator allows using Super Shock Rifles in every gametype. It gives you possibility to choose one of three Super Shock Rifle types and configure weapon's parameters such as ammount of damage dealt to vehicles, healing damage of Charge Super Shock Rifle's secondaty fire and some more. Enjoy!
Download ut4mod version
Download zip version
Instagib skull mutator 
This simple mutator displays instagib skull in server browser so players could easily know server is 'Instagib' type. I strongly recomend using it with Instagib4ever mutator.
Click here for other usefull simple mutators
BloodLust mutator version 0.5
This mutator makes every player's life drains every second and the only way to increase it is to to hurt/kill someone. The amount of life taken from a victim will be added to player. Mutator is fully configurabe and it is recommended to custom configure it to different gametypes/maps.
InstaIon mutator
Shortest description of this simple mutator is one word: Pwnaaage! This one is equivalent of InstaGib mutators but instead of Super Shock Rifle every player will get Super Ion Rifle! This weapon is capable of destroying heavy vehicle with single shot and has been designed as InstaGib equivalent for Assault and Onslaught game types... It's OBLITERATION time! ;)
If you are Unreal Tournament 2004 server admin then here you can download the zip version of this mutator. Simply unzip archivum to system subdirectory of your Unreal Tournament 2004 main directory.
Note: This mutator has been superseded with "InstaGib 4Ever" mutator.
Some of simple mutators made by me:
Ownage Mutator version 2.0
This mutator is dedicated for use on clanservers. It will display a message informing all players that clanmember has joined the game. It will also play 'Ownage' sound whenever clanmember joins (can be disabled). Mutator needs to be configured in order too work by providing clantag and specifying whether clantag is at the end or at the beginning of clan member name.
Gravity Control
Define your own custom gravity. Works with all game types.
Enpowered Assault Rifle
This mutator allows to increase power of default Assault Rifle (configurable). Install it, get double Assault Rifle and do some ownage. :) But watch out not to overpower it or it will become most powerful weapon in game. ;)
BoostDodge mutator
Enables boost dodging for players. There is a bug in build in 'UT2k3 Style' mutator that do not do this (after enabling fast weapon switching it it returns and code that was supposed to enable boostdodging is never executed. You can use this mutator to enable boost dodging. :)
Good Combo Speed
Restores default time for Adrenaline Speed Combo so it lasts as long as other adrenaline combos.
Instagib skull mutator
Using this mutator will enable instagib skull in server browser for your server. Recomended for use with any custom Instagib mutator.
Note: These mutators have been written over 5 years ago and I do not provide any support for them anymore.