The questions that ask for the "best" are impossible to answer.
I have to guess you are asking about patch lubes.
The only answer possible, and that will be unsatisfactory for you, is the one that works best in your rifle for you.
There are skillions of different concoctions for patch lube.
Some of the most popular involve beeswax/oil mixes. Olive oil, peanut, castor, etc. all work well.
Some involve the use of water soluable oil and water.
There are chemical mixes that are far from historically accurate.
There are commercial lubes that might or might not be any good.
To start, I would suggest you make up a mix of beeswax and peanut oil. I make into a semi-soft cake that can be rubbed on the patch cloth.
Do some searching here. This is an often, very often, discussed subject on the forum.