Conventions I have are:
- Downloads folder is ephemeral, don't store/keep things in there I might want
- ~/scripts - personal scripts and one offs
- ~/Documents/projects/[subdir] - any tech project I may be working on, gets homed here
- /tmp - always mount it
noexec
I also start off allocating ~ 50GB to / (root) volumegroup. Wine and proton have been taking up nearly the full space though, may need to expand it on my desktop soon.