The data for glitch Pokémon Pokédex is retrieved from a specific location in the Game Boy address BUS. In Pokémon Red, this address should be the value of register de when a breakpoint is set to 10:436D and the Pokémon's Pokédex entry is loaded.
A good number of glitch Pokémon take their data from writable memory, including:
(You must have not set the glitch Pokémon's capture flag
to see its Pokédex entry)
Thanks to the Pokémon Red disassembly, we know the data is formatted like this.
*(Species string terminated by 50).
*Four bytes apparently affecting height and weight.
While the text code (usually?) begins with 17, which is apparently the "text far" command we could replace it with 08, which allows us to execute arbitrary code following the 08.
The addresses marked with an asterisk probably have the most potential to be abused. In particular D6 (B417) and DC (AA00), which is somewhere in the Hall of Fame data for SRAM bank 0.
When I caught a glitch Pokémon it appears that the SRAM was left open, so hopefully we may be able to add a bootstrap code here to items or a different location to execute arbitrary code, provided that we catch a 0xD6 or 0xDC with the LOL glitch.
Chances are if you are able to catch these glitch Pokémon using the LOL glitch you already have access to the expanded items pack, which sadly makes this glitch unnecessary as you could modify the map script in the expanded items pack or bring up an 8F for arbitrary code execution but it's still a nice glitch.