Here are some of tested and suggested mods for Redneck Rampage. If you have more that you'd like to share here is the exact place. Note. It is better to test each mod with gog installer first before you add new one to this topic.
1. rrconed
Gives player 100000 health 999 ammo and other things.
http://files.filefront.com/rrconedzip/;1425990;/fileinfo.html
2. hulkgame
Makes player look like hulk, and other things.
http://files.filefront.com/hulkgamezip/;1425988;/fileinfo.html
3. xtrainer
A modified level and cons thats supposed to help hone your multiplayer skills.
http://files.filefront.com/xtrainerzip/;1425991;/fileinfo.html
4. gutspak
Adds more blood and guts to the game.
http://files.filefront.com/gutspakzip/;1425987;/fileinfo.html
5. cacopa
Makes all the UFO's in Redneck appear as the Cacodemon from Doom.
http://files.filefront.com/cacopazip/;1425985;/fileinfo.html
6. cootgame
Makes the player look like Leonard.
http://files.filefront.com/cootgamezip/;1425986;/fileinfo.html
7. pigcon
R 66 con, that when used in Redneck, makes the pigs go 'crazy'.
http://files.filefront.com/pigconzip/;1425989;/fileinfo.html