Roboform some folks claim will do that. I find that using Firefox as my browser there is enough stuff kept in memory that for most fields all I need to do is type in the first letter and my drop down list will have the answer I want. I find this also useful when entering redundant forms where you have a question such as "Did the teller suggest other bank products and services?" and they did not, so you click 'No' and the next question is "If 'no', explain". Since I am not a psychic who knows the teller's inner motivations, my most normal answer is "The teller mentioned no other bank products or service." As soon as I type in the letter T, my drop down has the answer there, ready to click to fill the space.
It is important, however to watch what is being put in the spaces of an application or report because sometimes Firefox will draw options from odd places and I noticed recently that for the above example, for some reason "Thelma" is now one of my options (the employee name from a recent shop by a totally different company). Don't know how that works