I hope this isn't an ignorant question, but I wonder if there is one place that all the b'rachot are written down, and if so, where is it? Are they all in the Mishnah?
They are written down several places, along with their various rules. The source for them (as well as reference to the various sources) is the sixth chapter (Keitzad Mevarchin) of the Gemmarra Tractate Berakhot, starting on page 35a. The Ayin Mishpat Ner Mitzvah section of the page (found in the upper corner of the outer margin) will tell you where to locate the halakhot discussed on each page in the appropriate Jewish legal codes (which will also there have the Berakhot and their rules).
In the book 'Birkhoth Eliyahu' the English version You will find all of them in Hebrew and English with transliteration. You can find there all the types of food + photos with their blessings