less
less -S
-S will disable soft line breaks within less, allowing horizontal scrolling.
Tailing Files
Use less +F instead of tail -f. It works the same, but supports interrupting the stream with SIGINT to e.g. search around, and then can resume tailing by hitting F again.
Doing so will even then highlight the search pattern in the future text.
less +command
Passing +command will run the given command each time a new file is opened by less.
Filtering Lines
&pattern will filter lines only matching the given pattern.
Opening EDITOR
Hitting v will open the file in an editor.