Travelling, but start by looking up Doom wads and Duke Nukem Build engine mods.
These were so plentiful they were put into compilations, and the best were even repackaged with the game in later releases.
Again, tons of playformers and fps titles would previously offer characters as unlocks as well as customization equipment. The Tekken series up through 5 had SO MUCH GEAR. Virtual Fighter up to VF 4 EVO. Fighting games were actually huge with this, and only Soul Calibur seems to have kept it around a bit. They still sell customizatipn packs I believe, but they offer FAR more out of the box than average.
Could list more but unfortunately about to lose signal.
sorry, I am just now realizing I misread your post. I thought you had meant first party content when I originally read the reply. Yea I agree that there are a far good amount of fan made mods and content, it’s still prevailed into the current field. I love when games launch with steam workshop support. I disagree that that content doesn’t exist anymore though. I still play quite a few games that have a store system and have a functional mod workshop on the side.
I do agree that some companies are lowering their access to their API services, or having that as a secondary thought, but thankfully they aren’t at the point where they just won’t allow for third party content period. Well mostly anyway, there are a few oddities out there that have cheat software in place that won’t allow it but thankfully those are few and far between. I’m currently struggling against the urge to mod my elden ring run myself, because I know that trips the multiplayer AC which will remove networking features.
I did also mean first party content. To my point though was that popular mods were often also rolled into titles as officially sanctioned expansions later on. But first party titles also featured significant amounts of unlockable and customizable content. This didn’t begin with the monetization era.