Zachary Taylor. 2pp letter
signed and datelined "Head Quarters, 1st Brigade Army, 8 P.M. Camp about
10 miles East of Kissimmee", addressed in Taylor's hand to Maj. Genl.
Jessup, fascinating contents regarding campaign against the Seminole
Indians and a recently fought battle, postcript on back reads "P.S. I am
now writing without candle or pine knots as a substitute, in a cabbage tree
hammock in the centre of a large prairie on a very dirty sheet of paper,
which is the only one in camp", cover endorsed "On Public
Service", splitting along vertical file fold and along folds reinforced
with hinges, some staining (as mentioned by Taylor), still Fine, very rare
letter from the Seminole Campaign (Image) 
Zachary Taylor. Free frank
as Brigadier General "Z. Taylor Bt. Br. Genl. U.S. Army" on folded
cover addressed in another hand to General Jones in Washington D.C., red
"Savannah Geo. Jun. 3" circular datestamp and matching "Free", 1839
docketing inside, vertical file folds and slight splitting along folds,
Very Fine and choice free frank (Image) 
Zachary Taylor. Bold free
frank "Free Zachary Taylor" as President on cover to
Louisiana, red "Washington D.C. Free 26 Nov." circular datestamp, small
insect nibbling at bottom right, fresh and Very Fine, rare presidential
frank (Image) 
Millard Fillmore. Free
frank "M. Fillmore" on cover to Edward Everett in Cambridge Mass.,
"Washington D.C. Free Oct. 9" circular datestamp, intact red wax seal on
back, fresh and Very Fine (Image) 
Abraham Lincoln. Free frank
as President "A. Lincoln" on cover front only addressed in
his hand to "Any Head of Department, Please see the bearer, A.
Lincoln, Feb. 20, 1863", both signatures are perfectly clear, light
file folds away from signaturesVERY FINE. A RARE ITEM SIGNED TWICE AND WRITTEN ENTIRELY IN THE HAND OF ABRAHAM LINCOLN.
This item was likely written for someone seeking a favor, and Lincoln directed that person to any head of department. (Image)
Mary Todd Lincoln. Free
frank "Free Mary Lincoln" on cover addressed in her hand to New York
City, neat "Saint Charles Ill. 14 Dec." double-circle datestamp, receiving
backstamp, few repaired edge tearsFINE AND RARE FREE FRANK OF MARY TODD LINCOLN, WIDOW OF PRESIDENT ABRAHAM LINCOLN.
Illustrated in ASCC on p. 223 (Image)
Andrew Johnson. Free frank
"Free U. S. S. Andrew Johnson" as a U.S. senator on cover to
Heightstown N.J., neat "Washington City D.C. Feb. 13, 1859 Free" circular
datestamp, edge wear and edge tears, the free frank is Very Fine (Image) 
Andrew Johnson. Free frank
"Free Andrew Johnson" on oversize cover addressed to James Buchanan
at Wheatland Pa., with intact red seal of President of the United
States on back, some slight cracking as usually found on wax seals,
neat "Washington D.C. Dec. 12" circular datestamp, some edge wear partly
reinforced with archival document tape at top, otherwise Very Fine,
remarkable especially for the intact Presidential seal -- Johnson
presidental franks are scarce (Image) 
Ulysses S. Grant. Signature
as President on official imprint cover for "Executive Mansion, Secretary"
with "Secretary" crossed out, addressed to "Hon. H. Fisk, Secretary of
State, Present", fresh and Very Fine, probably carried privately
outside of the mails, Grant was the last President with free franking
privileges while in office (Image)