As James said the Most Visited button is present, by default, in both Seamonkey and Firefox. I don't have a Home button in Firefox, but I have a Most Visited button. In both programs, when I click on the Most Visited, I get a dropdown, which shows the locations. It will vary every day, depending on your History. Right now, I have 10 entries, mostly different from yesterday.
I think that I mentioned View|Show/Hide in regard to the Personal Toolbar, but if unchecked you will not see any of the Personal Toolbar items.
Here is an useful piece of info
. Most others is my Search were on how to remove the button.
But, you are not the only person who does not see the button. Check this. It may help
But, no matter what the button will provide a History. In my Firefox, which I use less than Seamonkey,, Most Visited starts with the two Tabs which are my Home (page).
I don't know if there may be differences between Themes.
finally, to test the possibility that the button was deleted, I did just that (right click|delete the Most Visited button, and got it back following the directions here
. I recreated the folder, called it Most Visited, and dragged and dropped it in the Personal Toolbar.
UserAgent: Mozilla/5.0 (Windows NT 5.1; rv:10.0) Gecko/20120129 Firefox/10.0 SeaMonkey/2.7