HTCFlasher (formerly known as HERMflasher) is a tool which allows you to flash ROMs on most current HTC devices. It has some extra features that the original HTC RUU doesn't have. For example, it can present a serial prompt to the bootloader (replacing mtty), or it can dump NBH file contents (.nb ROM parts).
eINIT is an alternative init system. It's quite fast, since it can potentially be used without the help of any scripting at all, but it is still flexible and extremely modular. The focus is on speed and parallelisation, mostly with embedded devices and low-downtime servers in mind, and benchmarks do suggest that it's doing a fairly good job at that. It compiles cleanly (and should thus work, provided someone writes appropriate modules) on Linux, FreeBSD, and Darwin/Mac OS X.
cdrtools (formerly cdrecord) creates home-burned CDs/DVDs with a CDR/CDRW/DVD/BluRay recorder. It works as a burn engine for several applications. It supports CD/DVD/BD recorders from many different vendors; all SCSI-3/mmc- and ATAPI/mmc-compliant drives should also work. Supported features include IDE/ATAPI, parallel port, and SCSI drives; audio CDs, data CDs, and mixed CDs; full multi-session support; CD-RWs, DVD-R/-RW, DVD+R/+RW, BD-R/BD-RE; and TAO, DAO, RAW, and human-readable error messages. cdrtools includes remote SCSI support and can access local or remote CD/DVD/BD writers.