The best resources I have found are two books in Boston's "Genalogical Society" library on Newbury Street. (There is a day-use fee for non-members.) One of the books is a one-of-a-kind handwrite, and must be used in the library. The other was published by the Lycoming County, Pennsylvania, Historical Society, and it is available for purchase from them (for about $15).
Most or all of the Maine Toziers/Tozers are descendants of Richard Tozier/Tozer, who homesteaded in Kittery, Maine in the late 1650's (1658?). Richard married Judith Smith in Boston in 1654. He emigrated from Devon, England. Judith's origins are unknown to me. Obviously, both immigrated sometime between 1623 (the first voyages to New England for which full passenger manifests are not available on-line) and 1654. There is much information about the life of Richard and his immediate descendants contained in those two books - though it is a bit scrambled, occasionally contradictory, and takes work to decipher.
Good luck trying to trace your lineage all the way back to Richard, as there are thousands of Maine Toziers now, many with identical names (the first American Elizabeth Tozier was one of Richard's daughters).
My best suggestion is to get the Lycoming book on Toziers and Related Families. If you are very lucky, you might be able to find a connection between the earliest Toziers and the most distant direct relatives you can trace yourself back to. If you only know your roots for one or two generations, your chances are slim. I am a twelfth generation descendant of Richard, and I was only able to trace my roots because my ancestors kept moving from frontier to frontier. If yours stayed in Maine, you will likely find the trail lost in the maze of thousands of Maine descendants.
There are major family branches radiating from places like Massachusetts, Connecticut (by the 2nd generation), Pennsylvania (by the third), New York, New Brunswick (by the fourth or fifth), Wisconsin (by the fifth or sixth), and Kansas (by the sixth or seventh). If your family roots can be tied to any of those branches outside of Maine, your chances improve somewhat.