Yatse Custom Commands
The Yatse Android app is a remote control for Kodi. It supports adding arbitrary JSONRPC commands.
I haven't worked out how to execute specif functions withon Addons yet.
Reference: https://kodi.wiki/view/JSON-RPC_API/v12
Example curl commands for testing
curl --data-binary '{ "jsonrpc": "2.0", "method": "Addons.GetAddons", "id": "mybash"}' -H 'content-type: application/json;' http://kodi:[email protected]:8080/jsonrpc