The Monitoring Group has published an Excel-based tool to help trial teams design trial specific monitoring metrics, triggers and associated actions, to be included in a trial monitoring plan.
The tool includes a number of worked examples to provide additional context.

All metrics listed in the tool are generic prompts, which are routinely used by many Clinical Trials Units (CTUs). However, it is expected that these are selected and tailored to the individual trial and inline with CTU processes.
Download your copy of the guidance here.