If I type a part of a previous command in and then press the up arrow in fish it will only cycle through history records that contain that as a substring (which is really the killer part of the feature).
(Yes I know you can do similar things in bash but you have to press other keys to put it in the history search mode)
# - when performing completion in the middle of a word, do not insert characters # from the completion that match characters after point in the word being # completed
set skip-completed-text on
set colored-stats on
set colored-completion-prefix on
set blink-matching-paren on
set expand-tilde on
set history-size -1
set history-preserve-point on