Monks are the only Square profession without access to Shield Maneuvers, and yet they can 2x in Shield Use. There are a variety of maneuvers in the shield list that would be ideal and obvious for Monks. Considering it would be a significant TP investment, and would reduce their MM and Dodge chance, it sounds like a reasonable trade-off for Monks to learn shield use, and train maneuvers.

Based on the available options, the following maneuvers appear to fit the profession well in both lore and balance:

Shield Bash
Small Shield Focus
Medium Shield Focus
Shield Swiftness
Shield Mind
Shielded Brawler

This would be a significant improvement to Monk training options. By spending TPs, they unlock additional DS options, can improve their CvA by training in a shield focus and equipping an ensorcelled shield to better protect from warding attacks. They will have to sacrifice additional training options as well as suffer the dodge penalty, and MM penalties associated with having a shield equipped.