What are good ways to farm Dragonflight Renown?

Hey r/wownoob,

I'm a PvPer who's completely ignored the PvE side of the game (aside from Wrathion and Sabellian rep and the odd M+ here and there), but I'd like to get my renown up with the four major factions to unlock some cosmetic rewards now that I've hit my (relatively humble) rating goals.

What are some good, efficient/fast ways to farm renown? I have Valdrakken Accord somewhere in the teens, but the rest are single digit.

Thanks in advance!