darcs [0] patch theory was a predecessor to OTs/CRDTs (and a predecessor to git as well; in some ways it is the "smart" to which git was named "dumb"). When it works and performs well it is still sometimes version control magic.

pijul [1] is an interesting experiment to watch, trying to keep the patch theory flag flying and also trying to bring in updates from OTs and CRDTs as it can.

[0] https://darcs.net

[1] https://pijul.org/