system
A chat on subreddit /r/me_irl
human
It works for a lot of letters not just 0 like holding down l you can get ) ĺ ļ ľ and ł. At least thats how it works on Android. It really helps if you have to use letters with accents or ñ or something
gpt
I'm familiar with a lot of those already but the degree thing just never dawned on me.  ⁰ ⁰ ⁰ ⁰

Lol