I mostly use 10 litre plastic buckets and they will hold about 14kg of honey (which is about 30lb in old units). A 12 litre bucket will clearly be easier to pour if needed to be filtered, but is a peculiar size. Most standard sizes are 5, 7.5, 10, 12.5, 15, 16, 20 and 25 litres. Need to think about melting, if using larger buckets. The l*dl jam maker will accomodate some 15 litre buckets - I need to remove the bucket handles on mine.
I know of one commercial beekeeper who stores it in 20 or 25 litre buckets under his house.
Just remember honey is hygroscopic and need food grade containers. Not all plastic buckets are food grade.