Plymouth

Plymouth is used to show splash screens during system boot and shutdown. It is a more modern alternative to fbsplash and provides flicker-free animated boot splashes with support for progress bars, solar flares, and other nifty things. In addition to OpenRC, it also has full systemd support. Since it is a boot splash tool, Plymouth does not provide background eye-candy for the ttys way fbsplash does (meaning it shows no decoration on your consoles after the system has booted).

Installation
can be installed using

Themes
After emerging Plymouth a number of themes will be pulled in automatically, however you can download more Plymouth themes from the internet and install them manually. You extract newly downloaded themes to the default Plymouth directory:

Make sure each new theme is contained in its own folder (just like the default themes that are installed) or they will not be detected properly by Plymouth.

Once you have extracted your new, additional themes you can check your work by requesting Plymouth to generate a list of all available themes. Do this by using the  command:

Assuming you want to select the solar theme as the system's default theme:

Kernel Configuration
Specific kernel options must be altered in order to get Plymouth working properly. Use the  command (or equivalent) in order to modify the kernel configuration.

It is highly advised that you disable the Linux bootup logo. On some systems it seems to cause problems.

KMS for Nvidia graphic cards using the closed source official Nvidia drivers
To use the official Nvidia drivers see the wiki's official Nvidia article.

Initram Generators
There are currently two bootloaders that have support for Plymouth. Either one will produce essentially the same result, so it is your choice as to which one you use. This article does not go into any detail at all on troubleshooting failed results, so you should probably choose the one you are more comfortable with. Using Genkernel-Next is recommended.

Installation
At this point in time normal genkernel cannot create an initramfs with a Plymouth theme included. Therefore, in order to proceed, you will need to select either dracut or to build your initramfs with a Plymouth theme included. From this point onward this configuration guide will continue presuming you will be using genkernel-next since it is marked stable in the Portage tree and is essentially a drop in replacement for "normal" genkernel, however instructions for Dracut will be provided. The "plymouth" use flag needs to be enabled in  in order for genkernel-next to emerge properly for Portage:

If you are using genkernel-next you need to skip the Dracut section that immediately follows..

Dracut
Dracut is an alternative initram generator created by the Fedora developer team. Before you read the rest of Dracut guide know this fun fact: both Plymouth and Dracut are cities in Massachusetts. Imagine that!

Installation
For Dracut installation instructions follow this link.

Configure Dracut for use with Plymouth
Add plymouth as a module to the file:

OpenRC Configuration
Use your text editor of choice to enable Plymouth and the Plymouth theme in genkernel-next's configuration file:

Additionally, you will need to edit to make RC non-interactive:

Regenerate the initramfs using the  command:

Make an update to your Grub2 configuration to enable the splash screen during early boot. Append the options "quiet splash" to the GRUB_CMDLINE_LINUX_DEFAULT variable, adjust the resolution in the GRUB_GFXMODE variable to match your desired resolution for your primary screen, and set GRUB_GFXPAYLOAD_LINUX to "keep" in order to preserve the graphics mode during the entire boot.

Finally, run the  command to update Grub2's boot configuration. This will set Grub2 to be sure to include the changes you made when you updated file above.

You are done! Congratulations on your new boot splash!

Systemd Configuration
Plymouth automatically registers itself with systemd to show a splash screen during shutdown/restart.

External Resources
Plymouth Source Code Page

An Early Gentoo Guide for Plymouth