I think you could add Hydra to the optional items, I feel that with the E crits and actives buff, it's a great item giving garen more aoe dmg along with E (with Black Cleaver the active does a lot of burst damage specially after applying the shreds because your total damage is amazing).
I still have to test wether one should get it after boots and BC though, but the lifesteal which is applied to your E can probably give garen enough tankiness to wait for the really tanky items like Randuin and Spirit Visage which has a lot of synergy with it since the lifesteal will heal even more infight. Imo that's a great idea if you're ahead and your team only has you and your adc as AD damage dealers, and maybe one could build it before BC since the armor damage will mostly help when your damage is high and BC has little health anyway.