Here are a few description options for the WordPress post tag “信件範本” (Letter Templates) in Traditional Chinese, ranging from concise to slightly more descriptive:

**Option 1 (Concise):**

> 各种信件范本，应有尽有。
>
> *Translation:* Various letter templates, all available.

**Option 2 (Slightly Descriptive):**

> 寻找合适的信件范本？在这里您可以找到各种类型的信件，包括商务信函、感谢信、求职信等等。
>
> *Translation:* Looking for suitable letter templates? Here you can find various types of letters, including business letters, thank you letters, job application letters, and more.

**Option 3 (More Comprehensive):**

> 收集了各类实用的信件範本，帮助您快速撰写邮件、书信和官方文件。涵盖多种场景，例如求职、商务合作、感谢信函等等。 节省时间，提升效率。
>
> *Translation:* Collects various practical letter templates to help you quickly write emails, letters, and official documents. Covers various scenarios such as job applications, business collaborations, thank-you letters, and more. Saves time and improves efficiency.

**Option 4 (Adding Keywords):**

> 信件範本，提供商务信函、感谢信、求职信、辞职信等多种实用範本。 快速套用，轻松完成写作。 範本下载，信件写作技巧。
>
> *Translation:* Letter Templates, providing various practical templates such as business letters, thank you letters, job application letters, resignation letters, etc. Quickly apply, easily complete the writing. Template downloads, letter writing tips.

**Which option to choose depends on:**

* **Your target audience:** If your audience is familiar with WordPress and will likely understand short descriptions, a concise option may be enough.
* **The content of your posts:** If your posts cover a wide variety of templates, a more descriptive option might be better for SEO.
* **Word count limitations:** WordPress typically has a character limit on the description, so choose the option that fits within the constraints.

Remember to consider adding relevant keywords to your description to improve your tag’s SEO. The last example includes a few good keywords.