I thought I'd go through the modding section over on the RG Steam forums and find all the available Rebel Galaxy mods and put them in one place. Before using these you might need to change the dates on the PAK files so that they'll work with patch 1.08 as most of these were made before that patch. A simple program you can use to do this with can be found here:

http://www.online-tech-tips.com/computer-tips/how-to-change-the-last-modified-date-creation-date-and-last-accessed-date-for-files-and-folders/

For those who are tech savvy you can aslo go to the command prompt in windows, navigate to your ...\steamapps\common\RebelGalaxy\PAKS and then type

copy /b DATA2.PAK +,,

Onto the command prompt where DATA2.PAK is the name of the modfile you want to update.

This changes its "made by" date to be the day you write the code, and voila! Old mods work again~ (props to Grey for the tip).

I'll add instructions on how to install the mods at the bottom of this post.
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Retrofitted (Darphnix): http://steamcommunity.com/app/290300/discussions/2/405691491120297253/
EDIT: From the mod creator-"SAVEGAME-BREAKER (Possible): I haven’t changed any IDs anymore, so updating shouldn’t break anything. If you’re unsure: Sell everything newly added through the mod before updating. "

This is a comprehensive mod that affects gameplay across the board. Check out the thread for more details. Good for those who have finished the game and want to try something new.

Mod to fix the audio spikes on comm chatter. (Frigidman)
http://steamcommunity.com/app/290300/discussions/2/343785574516712160/

Help End Slave Trading mod (Stabby <3 haimikki):
http://steamcommunity.com/app/290300/discussions/2/487876568225470636/

Replaces space slaves with illegal Spiced Loc-Nar Orb. For those who don't like trading live cargo.

Larger Holds (Stone Cold Jane Austen)
http://steamcommunity.com/app/290300/discussions/2/487876568220353351/

Pro Sparrow and Grud mercs (Stone Cold Jane Austen)
http://steamcommunity.com/app/290300/discussions/2/485624149152527625/

"This does not actually change anything in-game but how you 'hear' comms audio chatter that occur during flight/combat/escort. You should not notice a single difference to any conversations you have (didn't touch a single conversation file)."

All alien weapons and components available mod (Ifret)
http://steamcommunity.com/app/290300/discussions/2/451848854985112277/?ctp=2#c350533172700270275

Unlimited subsystem slots (Dark King)
https$://mega.nz/#!dFUFxIgT!ZK0ViU58t7IpqwiIkUmvORCKctER4pD0R6hTofIqjSU
(just delete the $ after 'https'-it's from the mod creator and is clean)

Merchant buy limit increased (Darphnix, Ifret).
Discussion thread here: http://steamcommunity.com/app/290300/discussions/2/405692224225241755/

Hellion available at most stations (Ifret)
http://steamcommunity.com/app/290300/discussions/2/451850468366501355/

No ordinance consumed (Ifret)
http://steamcommunity.com/app/290300/discussions/2/451850020331475617/

Random spawns of any difficulty/missions of all difficulties mostly unlocked/events unlocked
http://steamcommunity.com/app/290300/discussions/2/451852571445967906/#c405691147595618702

Tough Factions (Philpw99)
http://steamcommunity.com/app/290300/discussions/2/485623406947283770/

Roleplay Redux (Diffiulty change) (Zix)
http://steamcommunity.com/app/290300/discussions/2/485623406951772022/

Charon mod (philpw99)
http://steamcommunity.com/app/290300/discussions/2/485623406948767340/

Makes the last system available again.

Detail Scanner (Ifret)
http://steamcommunity.com/app/290300/discussions/2/485624040225070387/

Detail scanner no longer takes up a component slot.

Certain Militia bribes (Stone Cold Jane Austen)
http://steamcommunity.com/app/290300/discussions/2/485624149154022702/
When Militia scans you and detects contraband, attempting a bribe now has a 100% chance of success.

HELPFUL LINKS:
Modding guide-

Basic Modding Guide for Rebel Galaxy
A Guide for Rebel Galaxy
By: Ifret
The intent of this guide is to teach basic modding skills, for Rebel Galaxy, to the steam community. It is my hope that this guide helps you to create mods that you will enjoy and share.

<<MODS BELOW THIS LINE DO NOT NEED THEIR CREATION DATES ADJUSTED>>

All ships software/components x2 Cargo 2x (iorek)
Doubles the components and cargo capacity on all ships except the starter ship.
http://steamcommunity.com/app/290300/discussions/2/1456202492173938573/

2x cargo/components/booster shields, 5x ammo / capacity / 5x cost reduction.. et al (iorek)
http://steamcommunity.com/app/290300/discussions/2/1456202492173967102/

Stronger Particle Laser Turrets and Neutron Beam Broadsides (Reytholian)
This mod changes the Shield Damage for the Particle Laser Turret and Neutron Beam Broadside to be more powerful.
https://steamcommunity.com/app/290300/discussions/2/1457328927839023815/

Crazy engine speed (request from Pantherr) (iorek)
https://steamcommunity.com/app/290300/discussions/2/1470840994959535384/

Enemy Leech Nerf (helps reduce engine impairment)
https://steamcommunity.com/app/290300/discussions/2/1728701877484239821/

Sub Systems mod (new versions of components)
https://steamcommunity.com/app/290300/discussions/2/1735462352471575792/

Turnspit's RG Rebalancing (1.08b) (WIP-Projectile & Laser Turrets only atm)
https://steamcommunity.com/app/290300/discussions/2/3335371283878171199/

HOW TO INSTALL MODS:
Download the .PAK file
Copy the .PAK file into your RebelGalaxy\PAKS folder.
Important:
Never overwrite the DATA.PAK in the PAKS folder
The mod .PAK has to be more recent then the DATA.PAK
When using 2 or more mods the more recent .PAK file will always overwrite the older ones. This is important if mods us the same files and/or the same new IDs in the files which will result in crashes.
(thanks to Darphnix for the info)

Rename each successive PAK to a higher number. It should like like this-
DATA.PAK
DATA2.ModName.PAk
DATA3.ModName.PAK
etc.

Finally you need to change the creation date of the mod to the current date. All you do is use freeware called BulkFilechanger. http://www.nirsoft.net/utils/bulk_file_changer.html
This is because mods made before the last patch won't work unless they were created after it.

Modding tools-
http://steamcommunity.com/app/290300/discussions/2/487876568237886960/
Mod explorer-
http://steamcommunity.com/app/290300/discussions/2/451848855006204082/

Modding guide:
https://steamcommunity.com/sharedfiles/filedetails/?id=551447922

If I've missed anyone's mod or you feel something is wrong please let me know and I'll do my best to correct it ASAP. Happy modding!

PLEASE LET ME KNOW IF ANY OF THESE MOD LINKS LEAD TO BROKEN MODS OR MODS WITH NON-WORKING LINKS!