I think both Chris and Ken have highlighted the point that you are probably a little late attempting to book for 2019.
If you are successful, then one wreck I would recommend is the Leopoldville.
She was a liner being used as a Troop ship when she was torpedoed by U486. She was carrying US GI's from the 66th Infantry Division. Almost 800 lives where lost. So historically significant to the USA with a story worth telling.
She is near Cherbourg. Quite deep, in the 40-50m zone. A huge ship on her side.
The Duplex Drive Tanks are also an interesting dive, although a tank is a very small dive site. They where modified Sherman Tanks, designed to float, with a propellor driven by the tanks engine. Unfortunately most where swamped before reaching the shore, leaving the landing troops without armour.
The landing sites where Utah, Omaha, Gold, Juno and Sword. The Americans landed at Utah and Omaha. I think it would be accurate to say that the American forces had a very rough time of it during the landings.
The first in were the RN frogmen, whose task was to clear the underwater obstructions to allow access for the landing craft. H hour was 06:30 for Utah and Omaha (giving them the element of surprise), then 7:25 for Gold and Sword, finally 07:35 and 07:45 for Juno.
It's a long time since I dived Normandy.
The issues I remember relating to Normandy.
The Seine Bay is quite exposed to the prevailing weather. If the weather is poor during your visit it can be very rough. If the weather is poor preceding or during your visit the visibility can be quite poor. The bottom is mainly sand, so any rough weather stirs up the sand, which then remains in suspension for some time.
When conditions are good, the visibility and diving can be exceptional.
As Chris said. Do not remove anything from the seabed or wrecks. The French are very strict about this. If they board and find anything, they will potentially impound dive kit and the boat.
One book I do have on the Normandy Dive Sites is
D-Day Wrecks of Normandy written by Mark James ISBN 0-9531856-0-5