So, I'm new to the comments but just wanted to put my 2 cents into the novelties.
To me, any sort of "exit" sign would be along the lines of ESC, Backspace, Del and not really so much on the theme of a Shift or Enter key.
I'm not really feeling the Edison bulb novelties. IMO, they just look too hand drawn, maybe having a more uniform look to them and cleaned up. But maybe doing some sort of "Secret of the Ooze" canister from the TMNT movie, put a glowing spider for Spider Man reference? There's maybe some references to 1950's movies that all had "Attack of the 50 foot ____" so maybe giant ants attacking a building?
1u keys - LOVE the Lego faces for the skeleton and ghost, but I'd be curious if that would come into a license issue. Same goes for the Lambda, as they had to license it from Valve (at least if you're using the same Half-Life game Lambda). Ones I feel would be required are toxic, biohazard, radiation warning symbols. I like the flask and caution signs that were rejected earler. Not really a fan of the gems and geometric ones. I just don't see them fitting the theme.
Ideally 12 for the F keys and then 1 (Escape Sign running out door) for ESC. Throw in something for mute, volume up/down, calculator for R1.
Some other ideas for 1u- Gas Masks (WW1, WW2, modern Special Forces), Glowing Spider, Alien face (ideally Alien movie with acid dripping from mouth but can be traditional Roswell alien), Dial Clock (although early GID clocks with Radium had glowing numbers/arms), Vomit Emoji (maybe better in 1.25u), Giant crystal like rock that comes from a planet K, acid burn warning sign, Anglerfish (maybe 1.25u), glow bug (actual bug or old kids toy), 6 fingered hand, Troll toy face, (doubt it for license issues) but Slimer, Minecraft Creeper (again, probably license issue), jack-o-lantern, googly eyes, shifty eyes