time - This module provides the "time" command which prints the current time.
trig - This module provides trigonometric functions to GRUB.
tr - The "tr" command is provided by this module. This is the same "tr" command as seen in BASH and other shells.
Truecrypt - Truecrypted MBR partitions require that this module be loaded so that GRUB can boot such partitions. TrueCrypt is an on-the-fly-encryption (OTFE) utility for files or partitions.
True - This module provides the boolean commands "True" and "False".
udf - The "udf" module provides support for the Universal Disk Format (UDF).
ufs1_be - Support for the Unix Filesystem v1 with big-endian is provided with this module.
ufs1 - Support for the Unix Filesystem v1 is provided with this module.
ufs2 - Support for the Unix Filesystem v2 is provided with this module.
uhci - This module provides support for the Universal Host Controller Interface (UHCI).
usb_keyboard - USB keyboards are supported with this module.
usb - USB devices in general are supported with the "usb" module.
usbms - USB mice are supported by this module that offers features needed for USB data streams.
usbtest - USB support is tested with this module.
vbe - VESA BIOS Extensions (VBE) is a specific VESA standard that this module supports.
verify - File signatures can be verified using the "verify" module.
vga - This module provides VGA support.
vga_text - This module provides the text-only (VGA) mode.
video_bochs - This module provides the Bochs video driver.
video_cirrus - This module provides the Cirrus video driver.
video_colors - Many functions related to color come from this module.
video_fb - This module is for the video framebuffer.
videoinfo - Various information concerning the graphics can be displayed using the tools that are part of the "videoinfo" module.
video - This provides code needed for various video modes.
videotest - The video settings can be tested using this module.
xfs - GRUB uses this module to gain support for the XFS filesystem.
xnu - This module provides support for XNU kernels (like OS X).
xnu_uuid - This module converts the 64-bit UUIDs to the 128-bit UUIDs used by Xnu kernels.
xnu_uuid_test - This module is used to ensure that two 128-bit UUIDs match.
xzio - This module provides read and write support for xz-compressed files.
zfscrypt - Encryption tools for the ZFS filesystem are in this module.
zfsinfo - This module displays various information about a ZFS filesystem/partition.
zfs - GRUB uses this module to gain support for the ZFS filesystem.