There are 3 repositories under ghidra-decompiler topic.
Comprehensive toolkit for Ghidra headless.
Translates a high-level declarative description of a simplification rule for Ghidra's decompiler into the C++ code that is required for the decompiler to apply the rule.
Bindra - Ghidra decompiler integration for Binary Ninja
Exports an executable into C code via Ghidra.