I'd like to have a logo edit / sbubby sub.
Also, some niche ones that aren't there yet (AFAIK):
buildapc : PC building help
SavageGarden / carnivorousplants: subs aimed towards tending bug-eating plants
hardwaregore / firmwaregore / softwaregore / technope : subs based around faulty hardware and firmware, sometimes destroyed hardware, or badly designed software
cablefail : pictures of bad cable management and the chaos of cabling in general
itsaunixsystem : sub based on overly fake or wrong tech in the media
PBSOD : faulty kiosks and such displaying error messages in the open
spicypillows / spicybricks : sub based on the pictures of swollen batteries of any kind, with the "bricks" being UPS batteries
dankpods / battrees : Australian youtuber who yells at several portable music gadgets and headphones, the battrees one being pictures of off-brand batteries, mostly PKCell batteries, but can also be several others as well.
techsupportmacgyver : instances of crazy fixes that ended up working
termux : sub for the Termux project
ITRage (likely a replacement for iiiiiiitttttttttttt) : information technology-related rage posts
headphones : not sure if there's a sub there for headphones and IEM related stuff so I guess there could be one.
justrolledintotheshop : automotive repair shop employee's findings when working on vehicles
Another, much more niche music, streaming and TV-related:
kpop : for Korean music news and updates, discussion (with objective viewpoint)
kdrama : news and updates about Korean drama series, reviews, discussion
kdramarecommends : recommendations for Korean drama series
trigger (or maybe studiotrigger) : discussion and updates on anime made by Studio Trigger
webtoons : webtoon series discussion
animemusic : sharing music featured in anime series
This all I could get from the top of my head currently.