An old saddle maker told me that olive oil works great for leather, and he was right.
If you use vegetable oil, you may want to filter it, or use one of the less expensive more processed types, since there’s a chance some vegetable oils can ho rancid.
Saphir, an old French company that manufacturers high end leather care products Uses Almond oil in their suede waterproofer, and it also is listed as a moisturizer for leather.
Tarrago, a Spanish brand of leather care products uses Avocado oil in their Leather Lotion.
Otherwise, for non-vegetable oils, neatsfoot oil, lanolin, beeswax, royal jelly(from bees), are all used in leather creams and conditioners.
Mink oil is used as well, but few mink oil treatments have significant amounts of mink oil.
Mineral oils are also used, But some don’t think the mineral oil is good for leather.