Yes ABC and Little Brownie bakery are the only companies that make official Girl Scout Cookies. As stated each bakery has their own name for some of the standard varieties. The 'extra' cookies are individual to each bakery. These varieties change periodically.
My area council - Chesapeake Bay Girl Scout Council - has this on their website:
Licensed bakers can offer up to eight varieties of Girl Scout Cookies®; only three types are mandatory: Thin Mints, Do-si-dos and Trefoils. The national Girl Scout organization reviews and approves all varieties proposed by the bakers. Any of the five optional Cookies can be changed every year. Suggestions for new Cookies are welcome, but the national Girl Scout organization can make no promise to use them.
Each Girl Scout Council chooses which bakery to buy their cookies from. They look at several factors including theme and support materials for leaders and scouts, cookie varieties, of course price, and other factors. Some councils sign multi-year contracts to get better deals, some evaluate the deals offered each year.
Each council sets the cost they will charge for the cookies. Each council also determines how much of the profit goes to troops and how and what prizes are awarded to scouts according to how many boxes they sell. Sometimes councils give troops the two options of choosing prizes for the scouts. The standard method is offering patches, stuffed animals, or other trinkets provided from the bakery from the years theme earned according to how many boxes a scout sells. Some councils also give troops the option of not offering prizes but give the troops more ca$h for each box sold.
If you want Girl Scout Cookies there is a girl scout out there that would love to sell some to you. You may have to look for her though. My council has an 800 number to call and your request is forwarded to a troop in the area where you live. I know DISers are a smart bunch of women and with some internet research I'm sure you could find a scout willing to sell you any number of boxes.
My council also allows customers to purchase cases of cookies that are donated to charity. The program is called 'Operation Taste of Home'. 60% of the cookies are donated to our troops through the USO at Dover Air Force Base located in our council. The other 40% of the cookies are donated to local charities throughout the council.
I had a blast serving as the Area Girl Scout Cookie Manager. I worked with about 40 troops. I trained each Troop Cookie Mom so they could train their scouts, ordered their cookies, tracked cookie payments to the council, and helped with problems.
This program is a great learning experience for girls and funds the majority of their troop activities for the year. Thanks for your support!!