I'll start with this picture. It was kinda the catalyst that made me want to start this thread. It shows which states require both a front and back license plate (blue) and states that only require cars to have a license plate on the rear (green). There are 19 states that don't require both plates, including Arizona and New Mexico as current DLC's.

Links to provided state's and their details:
Alabama | Alaska | Arizona | Arkansas | California | Colorado | Connecticut | Deleware |
Florida | Georgia | Hawaii| Idaho | Illinois | Indiana | Iowa | Kansas | Kentucky | Louisiana |
Maine | Maryland | Massechusetts | Michigan | Minnesota | Mississippi | Missouri | Montana |
Nebraska | Nevada | New Hampshire | New Jersey | New Mexico | New York | North Carolina |
North Dakota | Ohio | Oklahoma | Oregon | Pennsylvania | Rhode Island | South Carolina |
South Dakota | Tennessee | Texas | Utah | Vermont | Virgina | Washington | West Virginia |
Wisconsin | Wyoming | Washington D.C. |
As I post each state's standard and specialty plates, I'll update the list and link to each post! If anyone has any updates on the designs or wants to fix any errors that I made, please comment and I'll be sure to update each state's post. I’m going to avoid the current DLC’s for the moment because that research is seemingly done! If anyone from those states sees that they’re wrong and wants to share, I’ll link your post into this main post like all of mine are.
*Additional Information: Many states in the United States, and the provinces of Canada, are members of what's called the International Registration Plan or IRP. Before IRP, if a truck and trailer were going to be used for Interstate commerce, that truck and trailer would need to have a separate registration plate for EACH state that it intended to do commerce in. The IRP established a prorate plate system that allows trucks to take part in interstate commerce without needing multiple different license plates. These plates are referred to as "prorate" or "apportioned". Sometime they will say PRP for ProRate Plate, APP short for APPortioned, or the full word is written out. Similarly, there tends to be a difference between the tractor and trailer plates. Often the plates will begin with a different letter to indicate this, or sometimes will have PWR for PoWeR and TRL for TRaiLer. Other states won't indicate that the trailer plate is apportioned, and will simply say Truck Trailer, Semi, or other indication that it is a commercial trailer. Trailers not meant for interstate commerce don't need a prorate plate and will also receive a Permanent Trailer or Commercial Trailer plate.