I have the rest of the set figured out (or at least with guesses that I'm comfortable enough with), but this particular letter has me scratching my head. These are the only two examples of this letter that I found in six pages. (Lucky me, I ended up with three sequential sets from this timeframe. I do hope that trusted keyer is off for this project...)

The page is from 1706, and the handwriting is somewhat transitional, with a mishmash of Gothic, Kurrent, and modern. That said, the clerk seems to be mostly consistent regarding which forms of S, G, D, and J he uses, and this definitely doesn't match his standard forms of those.

T or Z, maybe? Or since the only given name I can think of that ends in "...bhart" or "...bhard" is "Gebhart", perhaps it's a G that's unlike every other G this scribe (or any other) wrote?