There are two usability tweaks that I would find it hard to live without: (1) red prompt on last-command failure, and (2) highlight what I type, dehighlight output:
Reason for 1 is obvious, 2 is more subtle: it helps my eye scan scrollback and identify what I've typed, which is what I'm scanning for 90% of the time.
Implementations vary, here's how I do it in zsh:
PS1='%(?.%K{cyan}%F{white}.%B%K{red}%F{white})XX%b%k%f %(?.%F{cyan}.%F{red})yyy%k%b%F{yellow}%(!.#.$)%f '. Duplication is evil, but AFAIK necessary because the conditional (error check) is%(?and I highlight both parts of my two-part prompt. Suggestions welcome for removing the duplication.zle_highlight=("default:fg=white")(on a Solarized Dark term, where the default fg color is light gray. Adjust to fit your needs).
As a longtime Goodreads user I'm kind of smitten with Hardcover. It offers nearly everything I want: good database, lists, status, searching. Also has responsive developers and a promising roadmap. The one thing it's missing is, sigh, my friends. hashtag-networkeffect. I'm a paying supporter.
I've been a paying supporter of Storygraph since its beta days, but I just don't really get it. Its social aspects are awful. Maybe it's great for automated book recommendations, but I have zero interest in that. I just want to see what my friends are reading, have read/reviewed, want to read. And I want to keep track of my books.
Bookwyrms looks promising but each time I try it I run into new stumbling blocks. I will keep playing with it, but for now my efforts are all on Hardcover.