Hi Damienne!
Welcome to the Disney Parks Moms Panel, and thank you so much for bringing this question to us hEAR! I'm the panel's resident glow cube expert; I love that these little beverage inclusions turn my drink into the star of the bar, and I also love that these tiny souvenEARs can be a bit repurposed later on - my Mouseketeer loves to play with them in the bathtub and pool!
I did a bit of digging, and currently the Ray Ray light up is a "glow clip" that hangs on the side of a glass and cannot be submerged in liquid like traditional color changing cubes. This little lightning bug is also an exclusive to the already exclusive Club 33. So sadly the only way to get a Ray of your own is to be like Princess Tiana and 'work real hard for what you want' and become a member, or, to know "friends on the other side." (But not in like an evil Dr. Facilier way, more like "be an invited guest" or know someone who knows someone who will be dining there and request this item.)
As far as other cubes and clips, during non-holiday times of year there are only a handful of options:
~ For "clips" that hang out on your cup, the current options are only available by purchasing a "Kids' Specialty Drink" found only at select
Table-Service Disney Dining Locations like Sci-Fi Dine-In Theatre Restaurant, Tusker House, Akershus Royal Banquet Hall, Garden Grill, Kona Cafe and a dozen more. This offering is a whole set, and the last time I asked I couldn't swap out the included "lite lemonade" for a more traditional soda. The description lists "character clip-on light" which is pretty vague, but for the last few years these have been Buzz Lightyear, Lightning McQueen, Tinker Bell or Ariel, and usually each restaurant only has two to choose from at any given time.
Trattoria al Forno used to have an exclusive Pascal clip-on, but I don't have confirmation if he's currently available or not.
~ For "cubes" that can be submerged in a drink,
Pongu Pongu in Pandora - The World of Avatar in Disney's Animal Kingdom Theme Park has two drinks that include a 'Glowing Unadelta Seed', and for a few bucks you can also purchase one on its own or add it to any of their other beverage options. Also in Animal Kingdom, the full-service bar
Thirsty River Bar & Trek Snacks has a floating lotus glow flower that can also be added to any drink or sold on its own. There used to be a few more submergible shapes that have since departed Disney, like a millennium falcon as well as a death star; however, you never know when you'll stumble upon a new shape or an old favorite as a limited time offering, so definitely keep your eyes peeled at all food and beverage locations, specifically for temporary display stand-up signs next to cash registers.
~ Lastly, more specialty glow cubes pop-up around halloween and the winter holidays, and the
Disney Parks Blog is the best place to lEARn of these additions.
I hope that this helped to plan your upcoming Disney Days, Damienne, and We'll See You Real Soon!
~Kristen