What it is: a 1-episode special with minimal plot and visual novel-style animation. But here's what matters, it lets you back into these characters' lives after the series ended, and that reunion costs nothing but time. The special doesn't try to resurrect the story. It just sits with them, lets them breathe, and reminds you why you loved them in the first place. If you finished Anohana and thought you were done grieving, this proves you weren't.
Menma e no Tegami is a single-episode picture drama special from 2012, tied to Ano Hi Mita Hana no Namae wo Bokutachi wa Mada Shiranai. The episode was released as an extra on the Anohana Fes. Memorial DVD and Blu-ray box set. Its genre labels place it as a blend of comedy and drama.