Shiori is a nice new Pinboard client for Mac that lets you find and add bookmarks. The app can be configured to have two separate keyboard shortcuts for adding and finding items; alternatively, you can click on the app's icon in the menubar and work with the dropdown menu (which also contains shortcuts for Refresh and Preferences).
The interface is clean and minimal, with tags highlighted in light blue/green; Shiori comes in the foreground with a list of the latest 7 bookmarks from your account (by default; you can show up to 10) and you can start typing to filter results. The app is extremely fast at retrieving items, and it supports abbreviations to look into bookmark titles, URLs, and tags. According to the developer, the app can get smarter over time by learning from your "habits" (I assume it means abbreviation use and choice of results in search).
There are other nice touches worth mentioning. There's a Private URL feature to automatically make URLs that match criteria specified in the Preferences private in your Pinboard account; when adding a new bookmark, Shiori can get the active webpage URL and title from the browser (Safari, Chrome, and Firefox are supported) and provide a list of recommended tags (a feature of the Pinboard API).
Shiori is simple, elegant, and fast. Get it here for free.