At really, if you create fixed patterns for the UX you will swim against the flow and limiting the user experience.
The design has patterns but UX doesn't.
The UX is based on research and tests to obtain results. And you must monitor the website and changes. The technologies update fast the user experience changes together.
I recommend you to create a culture of UX in your company. Everyone should think about the user first. Everybody can share tech news with all.
You also can create a routine of tests to identify issues or discover parts of your website that should be redesigned to keep the usability on a high-level. In this case, you need to define a responsible for the tests and what type of tests should be done and how frequently.
As soon as any problem is discovered, you should add to the task list and setting the priority.
From there, your team just need to follow the UX process (using the pattern Artifacts suggested by JazRo) that you also can design.