T - Z with garden pests will include one of the most difficult pests to get under control - Whitefly! Together with that, the larvae of the Vine weevil Beetle will play havoc with your plant's root system - often resulting in death with smaller plants. Observation of your plants on a regular basis may well alert you to what is happening underground - especially with the tell-tale leaf damage which is the hall mark of Vine Weevil Beetles.
Also at work underground in this list, are the potato-partial wireworms. Be aware that they are also a prblem for many plants - especially with fleshy roots - in the vegetable garden.
The garden pond might also fall prey to a pest especially if it has water Lilies - Nymphaea - Water lily Beetles.