Toxic had a short competitive run in Standard and caught the attention of Commander players, especially since its somewhat easier to win with 10 poison counters than 40 damage or 21 commander damage
There are many ways to build Commander decks and there are exceptions to most schools of thought
Ludevic, Necro-Alchemist and Kraum, Ludevics Opus both do neat tricks to give you card draw in a way that pushes benefits to your opponents (but more for you)
If someone other than you gets hurt somehow, spectacle costs are active
If youre like me and you love those long Commander games where any player that can overcome the next board wipe wins then, youll love Azorius
That strategy isnt particularly popular, but Maddening Cacophany only has one printing from Zendikar Rising, meaning that its supply is likely limited