I add some extra gameplay, comlexity and, of course, challenge to the game with - Remote Tech - TAC Life Support - SCANsat with fitting contract packs Also, I really want to recommend kOS to anyone who is familiar with coding basic. I mostly use part packages which bring completely new gameplay mechanics to the game, and do not only add variations of parts which are already in stock, like new egines. I won't list all packages I use, just the ones I consider mandatory for my experience: - KAS - KIS - Universal Storage When it comes to spaceraft design, I strongly depend on: - Tweakable Everything - TweakScale - Kerbal Engineer Redux And the other quality of life tools I use frequently: - Kerbal Alarm Clock - Precise Node - Trajectories (Not using it right now, as Stock Aerodynamics are not supported yet)