There are at least a couple of shapes referenced in chapter 5 of Schreiner's "Interpreting the Pauline Epistles (2nd ed)" that are missing in L6 sentence diagrams.
One is the "signpost." See the Master Symbols Chart on pg 91-92. Another is "stilts," where the top horizontal line extends to both sides of the vertical line (the horizontal line in L6 "stilts" only extends to the right of the vertical line, at least in LTR mode).
I haven't done a complete audit of Schreiner's symbols. Seems like a good project for a Faithlife intern. 
Thanks,
Donnie
