Some episode and webm statistics for Derpibooru:
-The most popular episode by image count is The Cutie Map, and the least popular is Owls Well That Ends Well
-Flutter Brutter, The Fault in Our Cutie Marks, Buckball Season, On Your Marks, Appleoosa’s Most Wanted, Made in Manehattan, and Where the Apple Lies do not have any webm uploads. Beyond all of them predating webm implementation, I see no common thread, though three of them are CMC episodes and a fourth has a speaking role from Apple Bloom…
-Relatedly, Crusaders of the Lost Mark, Do Princesses Dream of Magic Sheep, Top Bolt, Dungeons and Discords, Secrets and Pies, Viva Las Pegasus, Not Asking for Trouble, Fluttershy Leans in, and Brotherhooves Social each have 1 webm as far as I can tell…
-As far as I can tell, Cotton Sky, Lemon Crumble and Spur are the only characters who both appear in a webm
and officially have a speaking role who
do not have any of their spoken dialogue in a webm here on Derpibooru (Bloofy
technically has a speaking role uploaded here
>>2142020 as does Biscuit
>>2155983, while Spur only has
>>2155758 in which only Sweetie Belle and Scootaloo speak. Lemon Crumble has
>>2050358 and
>>1792527, while Cotton Sky has
>>2096761, both only speak in The Ending of the End Part 2 IIRC, and none of those webms are from that episode)