This is the fourth episode in the series about a Titan trying to expand their intellect. The other episodes are "Brain Food", "Knowledge", and "Head Fruit".
In the live action segment with Beast Boy doing a coin trick, the actor is wearing a shirt with a design of Beast Boy's costume on the front. This shirt just happens to be official Teen Titans Go! merchandise you can purchase from Cartoon Network's website.
The puzzle book the Titans are enjoying is Hidey-Town, the same important periodical that Cyborg was reading at the dentist's office in "Meatball Party".
Beast Boy wears his "Shakespeare" outfit again. He wore it for the first time in "BBRAE" (Part 1) when trying to impress Raven by reading her a love poem.
The hidden picture puzzle book that is titled Hidey-Town the Titans are viewing at the beginning is similar to a real series of books that are titled I Spy.
It also resembles the hidden-image illustrations that appear in every episode of Highlights magazine.
Beast Boy traveling back in time to touch fingertips with a monkey man and then becoming a supercomputer parody similar scenes from the 2014 film, Lucy.
When Cyborg mentions how the 10% brain myth is mostly used as plots for books, TV shows and movies, images appear that reference The Riddler, The Brain (his name once again misspelled as "Brian"), Brainiac, Lex Luthor, and Superman.
When Beast Boy turns into a full computer, his body shape and model looks somewhat similar to BMO, from Adventure Time, another show on Cartoon Network which Hynden Walch starred in.
When Robin refutes Cyborg's claim that TV shows are dishonest, an image promoting that a sixth season of the original Teen Titans series is coming soon suddenly pops up.
At 50% brain power, Beast Boy shares deep insights about that Titans. He brings up the dramatic inner struggles that are better associated with their more serious incarnations, such as Raven's need to control her emotions and Starfire's isolation from the people of Tamaran.
Beast Boy said that Starfire is the only alien on earth, but he's wrong. Superman and Supergirl are also extraterrestrial beings who lived on Earth after their home world Krypton got destroyed.
However, he could have meant that Starfire is the only Tamaranian on earth, which (not counting Blackfire) is technically true.
Beast Boy constantly getting frustrated over solving childish puzzles, even as his brain percentages go up.
Beast Boy not being able to solve the puzzles and raising his brain percentages to solve them.
The transcript for "Brain Percentages" can be found here.
The image gallery for Brain Percentages may be viewed here.