I suppose I would choose Darcs & Pijul for version control systems to bit into Git hegemony (& if you prefer Git hegemony, don’t use proprietary code forges).
Additionally just the general vibes of IRC & XMPP for battle-tested chat applications that are lightweight for clients & servers alike. These are the kinds of tools your next community should be built on if you want to minimize resource usage (data plans, storage capacity, battery, CPU churn).
When a repository is cloned lazily, darcs adds an entry in _darcs/prefs/sources, so whenever you use a commands which needs to work with all the patches, darcs try to fetch the missing patches using the entries from the cache, since the original repository was added to sources, it is also added to the cache (since darcs relies on the source file to load the cache).
You have all the code & fetch patches as needed. Not the same as a shallow clone, but if trying to not download the whole project history, this serves a smiliar goal.