The feature-rich alternatives you mentioned are exactly what I was thinking about (and using daily!).
Edit: I gave ble.sh a try, and it is super-cool-magic, but does feel slow with quite noticeable input lag.
The hardest part about leveraging the power of fzf is getting input into your --preview argument in the middle of some piped process. But that's also where it's true power becomes fully evident.
awk users have long had similar powers. And indeed you might find awk useful for reorganizing record separators in a pipe to fzf. But fzf is brilliant because it "just works" for 90% of cases.
I think we're probably going to see people sharing some pretty incredible workflows with fzf in the next few years. Something about being able to stick it in the middle of a Unix pipe just makes it really really special; it's compose-able!
[zsh-syntax-highlighting](https://github.com/zsh-users/zsh-syntax-highlighting)
[zsh-autosuggestions](https://github.com/zsh-users/zsh-autosuggestions)
Poster mentioned "modern alternatives exist" with good colorization options. Some of my favorite colorized feature-rich alternatives:
ls -> [exa](https://github.com/ogham/exa)
cat -> [bat](https://github.com/sharkdp/bat)
du -> [ncdu](https://dev.yorhel.nl/ncdu)
diff -> [delta](https://github.com/dandavison/delta)
In combination with all of the above, [fzf](https://github.com/junegunn/fzf) suddenly becomes a syntax-highlighter preview-pane via leveraging bat (or delta, as the case may be).