Sample tribute speeches (and what should happen in each section of a tribute speech) can be found on Special Speeches. Tribute speeches for a variety of holidays and special occasions can be read by using the various tabs to the side of the site.
For a less specific example, Synonym.com has a template entitled "How to Do a Tribute Speech" that has an outline. While there are no examples of full tribute speeches here, the steps are elaborated and more detail is given about how to address specific events (such as a family member's death or the finish of a long, much awaited project). References are also given, which lead to more detail and the information that was paraphrased.
One of the references is Write Out Loud. This source, the page entitled "Tribute Speech Guide," gives more detail on how to begin writing the tribute speech, choosing a topic and other important factors to keep in mind. More examples of when tribute speeches are used are given, and each example has a short description of what is often thought of when that kind of speech is brought up in everyday conversation. This resource also has specifics for writing a eulogy or a funeral speech.