Bob Budiansky, the creator and writer of the original Sleepwalker comics, also created Transformers like Bumble Bee, Megatron, and many others. During his time at Marvel, Mr. Budiansky was tasked with naming and creating bios for many of the Transformer toys. He also wrote the original Transformers comics for Marvel which laid the foundation for Transformers stories to come.
The posters in Rick's apartment are homages to Marvel Cinematic Universe directors and other writers who have connections to Sleepwalker. For instance, the Walking Dead poster is for Robert Kirkman who wrote a Sleepwalker one-shot comic years ago. There is a Slither poster and a What We Do in the Shadows poster, homages to early films from James Gunn and Taika Waititi, respectively.