REFInd

rEFInd is a boot menu and maintenance toolkit for UEFI and EFI-based machines. It can be used to boot multiple operating systems that are installed on a single non-volatile device. It also provides a way to enter and explore the UEFI/EFI pre-boot environment using an interactive shell, for example codice_1 . 
It was forked from discontinued rEFIt in 2012, with 0.2.0 as its first release.
rEFind supports x86, x86-64, and AArch64 architecture. 
Features.
rEFInd has several features:
Adoption.
rEFInd is the default Unified Extensible Firmware Interface (UEFI) boot manager for TrueOS.
The popular Manjaro installer "Architect" also adopted rEFInd by 2018.
Development.
GNU-EFI and TianoCore are supported as main development platforms for writing binary UEFI applications in C to launch right from the rEFInd GUI menu. Typical purposes of an EFI application are fixing boot problems and programmatically modifying settings within UEFI environment, which would otherwise be performed from within the BIOS of a personal computer (PC) without UEFI.
rEFInd can be build with either GNU-EFI or TianoCore EDK2/UDK.
Fork.
RefindPlus is a fork of rEFInd that add several features and improvements for Mac devices, specifically MacPro 3,1, MacPro 5,1, and equivalent Xserve.