Here are a few books I've read through Kindle:
Lonestar Reloaded series, 6 books, by Drew McGunn - An American Soldier in Iraq goes into a coma. He wakes up in 1836 in the body of one of the Alamo defenders.
Crossover Series, 2 books, by Walt Socha - Five people go back in time to 1054 North America. They help a Native American village against a local Indian warlord.
Arturo Sandus, 7 books, by Peter Rhodan - Man from the far-future ends up in 410 Roman Britannia. Time to restore the Republic and Modernize Ancient Humanity!
Sealion Drowning by Jon Zackon - What would actually happened had Operation Sea Lion occured with consenquences after.
Righteous Kill by Ted Lapkin - Modern Israeli soldiers go back in time to 1940 to kill Hitler and his patsies