Gnome normally brings their simple GNOME Document Scanner (simple-scan), KDE comes with skanlite or skanpage. xsane is an older GTK-based frontend, there's also the GIMP plugin using xsane. NAPS2 is an independent fully-featured frontend. And a lot of dedicated OCR software (including stuff like OCRFeederor Paperwork) also supports sane.
PS: even the basic tools support previews, then letting you select only the specific area you want to scan.