Instead of stranded 3 which is not coming out in the near future, there have been many mods (modifications) created for the game, with extra items, new gameplay and characters etc. This list contains finished/unfinished/abandoned mods, which are playable.

CStrike Mod

Excellent mod created by user Vectar666 which adds weapons from 'counter-strike' and 'portal'. for eg: ak-47, portal gun, m60, ect.

Czechsention Mod - The Czechstention mod was a very promising and large mod when it was being developed, certain features included cooking menu which had variables such as burning food if it was cooked for too long. There were many new models such as a cow, new units, and many items which had been remodeled for improvement even though these already existed. Unfortunately the project died and only the demo was released which didn't have everything planned for it. Nonetheless this was one of the best mods.

Gather Mod

An unfinished mod made by user gather and hasnt been released.

Survival Stories

A mod adding units items and objects but, nothing else.

Created by user UnIdEnTiFiEd

Kidnap Mod - The kidnap mod was created by the user HudaJan (who also helped with the development of the Czechsention mod) he modeled and scripted the game by himself. This is probably the neatest and most well done mod yet, every model had a clean well made look and there was one for every new item instead of reusing models, or simply creating bitmaps for it some of these new things included: a Motorbike, Primitive car, Submachine gun, flying carpet, and bad natives with bow and arrows. There are many others as well. The adventure mode has an interesting story and there is a currency you can use to purchase things instead of resources. There a re also several new skills one of which was stealing, and the likely-hood of a successful steal would depend if it was day or night. HudaJan then proceeded to start in a Taxi Edition, which was a very exciting idea for the followers on his mods, however sadly this was never completed or released. 

Shadow over the Pathoras - This modification was created by a group of modders named Wolf Soft. The story takes place in 1650 . The player controls William Wolf, a German navy officer, who accidentally enters the Pathoras, a kingdom ruled by the evil Darkan family. William must join his forces with the Pathoras rebels, in order to survive and win the war between Darkan family and rebels. The gameplay was a combination of action, adventure and logic puzzles. A demo was released in 2013 together with a bunch of trailers. In 2014 the mod was eventually cancelled (due to technical problems, bugs and lack of interest), despite the fact, that the full version was completed and the EN translation was almost completed too. Later that year the full version was accidentally deleted. In 2017 a remake was relased by Kloki38 (the founder of Wolf Soft) for GZDoom engine on the Mod DB. It´s based on the early unreleased beta version. 

Multiplayer mod - This is an unofficial modification of Stranded which implements the possibility to play together with your friends. Sadly, the project was later abandoned.  

Another mods: 

GTA Lienden  

Jurassic Park Mod

Lost in Space Mod

Ultimate Survival Mod

V666 Mod