GNOME Disks

vs

DiskImager

GParted is a free and open source partition editor for graphically managing your disk partitions. With GParted you can resize, copy, and move partitions without data loss. The software enables you to grow and shrink your C: drive, create new space for operating systems and attempting data rescue from lost partitions on your hard drives.

KDE Partition Manager is a utility software to help you manage the disk devices, partitions and file systems on your Linux-powered computer. With KDE Partition Manager, you can easily create, copy, move, delete, resize without losing data, backup and restore partitions.

A really simple open-source, GUI application that writes compressed disk images to USB drives and creates backups. USBImager is avalible for Linux, macOS, and Windows.
 

UNetbootin, short for Universal Netboot Installe is a tool that allows you to easily create bootable USB flash drives to install or try operating systems. This software is designed to be cross-platform and works with Windows, as well as Mac and Linux operating systems.

With Rufus you can format and create bootable USB drives. Rufus is free and open source and can format FAT, FAT32, NTFS, exFAT, UDF, ReFS that works across USB flash drives, keys, and memmory sticks.